James Acton
@nuclear-jim.bsky.social
Co-director of the Nuclear Policy Program at the Carnegie Endowment For International Peace. I spend a lot of time thinking about nuclear weapons, advanced nonnuclear technology, and escalation.
I feel pretty strongly the @nytimes.com has the wrong framing here. This isn't serious; it's pathetic.
I'd suggest something like:
"Trump throws social media hissy fit invoking nukes after public spat with ex-president of Russia."
I'd suggest something like:
"Trump throws social media hissy fit invoking nukes after public spat with ex-president of Russia."
August 1, 2025 at 6:56 PM
I feel pretty strongly the @nytimes.com has the wrong framing here. This isn't serious; it's pathetic.
I'd suggest something like:
"Trump throws social media hissy fit invoking nukes after public spat with ex-president of Russia."
I'd suggest something like:
"Trump throws social media hissy fit invoking nukes after public spat with ex-president of Russia."
As much as I deplore nuclear signaling by tweet--can't believe I just wrote that--I would NOT necessarily assume there's a been change to the US nuclear posture. The U.S. always keeps ~4/5 SSBNs at sea ready to fire.
August 1, 2025 at 5:50 PM
As much as I deplore nuclear signaling by tweet--can't believe I just wrote that--I would NOT necessarily assume there's a been change to the US nuclear posture. The U.S. always keeps ~4/5 SSBNs at sea ready to fire.
Ahem
(Deleted earlier version, which was missing caption!)
(Deleted earlier version, which was missing caption!)
August 1, 2025 at 5:42 PM
Ahem
(Deleted earlier version, which was missing caption!)
(Deleted earlier version, which was missing caption!)
Ah, yes, that crucial ninth significant figure...
July 31, 2025 at 3:29 PM
Ah, yes, that crucial ninth significant figure...
And, finally, given that hope is not a strategy, what's your plan to keep Iran in the NPT and to accept inspections--including of the 60% HEU that Israeli officials acknowledged survived the strikes. (12/12)
July 28, 2025 at 2:52 PM
And, finally, given that hope is not a strategy, what's your plan to keep Iran in the NPT and to accept inspections--including of the 60% HEU that Israeli officials acknowledged survived the strikes. (12/12)
Given the U.S. developed the uranium metal production process in the 1940s in a university lab with equipment from the 1920s, why do you suppose Iran will struggle to replicate the process outside of Isfahan? (11/n)
July 28, 2025 at 2:51 PM
Given the U.S. developed the uranium metal production process in the 1940s in a university lab with equipment from the 1920s, why do you suppose Iran will struggle to replicate the process outside of Isfahan? (11/n)
The U.S. did not even try to collapse the very deep tunnels at Isfahan where most of Iran's HEU was stored. Are you concerned that, in reality, the United States has clearly signaled the limits of ability to destroy underground facilities with nonnuclear weapons? (10/n)
July 28, 2025 at 2:51 PM
The U.S. did not even try to collapse the very deep tunnels at Isfahan where most of Iran's HEU was stored. Are you concerned that, in reality, the United States has clearly signaled the limits of ability to destroy underground facilities with nonnuclear weapons? (10/n)
What's Israel's plan for dealing with the HEU that Israeli officials acknowledge survived the attack?
Does Israel know the location of Iran's stockpile of centrifuge components, which have not been under monitoring since 2021 following the Iran Deal's collapse? (9/n)
Does Israel know the location of Iran's stockpile of centrifuge components, which have not been under monitoring since 2021 following the Iran Deal's collapse? (9/n)
July 28, 2025 at 2:50 PM
What's Israel's plan for dealing with the HEU that Israeli officials acknowledge survived the attack?
Does Israel know the location of Iran's stockpile of centrifuge components, which have not been under monitoring since 2021 following the Iran Deal's collapse? (9/n)
Does Israel know the location of Iran's stockpile of centrifuge components, which have not been under monitoring since 2021 following the Iran Deal's collapse? (9/n)
To close, some questions for Ignatius' source.
What happens if "activities" are being conducted too far underground for Israel to destroy? Do you expect the U.S. to attack again? If yes, what happens if the activities are too deep for the U.S. to reach? (8/n)
What happens if "activities" are being conducted too far underground for Israel to destroy? Do you expect the U.S. to attack again? If yes, what happens if the activities are too deep for the U.S. to reach? (8/n)
July 28, 2025 at 2:50 PM
To close, some questions for Ignatius' source.
What happens if "activities" are being conducted too far underground for Israel to destroy? Do you expect the U.S. to attack again? If yes, what happens if the activities are too deep for the U.S. to reach? (8/n)
What happens if "activities" are being conducted too far underground for Israel to destroy? Do you expect the U.S. to attack again? If yes, what happens if the activities are too deep for the U.S. to reach? (8/n)
Finally re timeframe, as Eric has observed, the claim that Iran is 1-2 years from the bomb is actually similar to pre-war estimates, including from NETANYAHU himself. (7/n)
July 28, 2025 at 2:49 PM
Finally re timeframe, as Eric has observed, the claim that Iran is 1-2 years from the bomb is actually similar to pre-war estimates, including from NETANYAHU himself. (7/n)
Ignatius is also inconsistent. Back in 2015, while generally supportive of the Iran Deal, he argued its 10-year timeframe (again, misleading) meant Obama was making a "big bet."
Now, an attack with much shorter-term effects is a success. (6/n)
washingtonpost.com/opinions/aft...
Now, an attack with much shorter-term effects is a success. (6/n)
washingtonpost.com/opinions/aft...
July 28, 2025 at 2:47 PM
Ignatius is also inconsistent. Back in 2015, while generally supportive of the Iran Deal, he argued its 10-year timeframe (again, misleading) meant Obama was making a "big bet."
Now, an attack with much shorter-term effects is a success. (6/n)
washingtonpost.com/opinions/aft...
Now, an attack with much shorter-term effects is a success. (6/n)
washingtonpost.com/opinions/aft...
Ignatius's oped is written as if it's a news story. The "news" in this case is that--SURPRISE!--an Israeli source backed up claims by the Israeli government! (3/n)
x.com/james_acton3...
x.com/james_acton3...
July 28, 2025 at 2:44 PM
Ignatius's oped is written as if it's a news story. The "news" in this case is that--SURPRISE!--an Israeli source backed up claims by the Israeli government! (3/n)
x.com/james_acton3...
x.com/james_acton3...
I know I'll be accused of war mongering by people who read just the first tweet, but to be clear, more bombing won't help. I'm not optimistic about preventing Iran from getting the bomb, but the best way forward is diplomacy. (4/n)
July 25, 2025 at 3:41 PM
I know I'll be accused of war mongering by people who read just the first tweet, but to be clear, more bombing won't help. I'm not optimistic about preventing Iran from getting the bomb, but the best way forward is diplomacy. (4/n)
Claims/implications that Iran may struggle to recover the highly enriched uranium that is probably sitting underground at Esfahan are just silly.
Digging debris out of tunnel entrances really isn't hard. (3/n)
Spice warning:🌶️🌶️🌶️
Digging debris out of tunnel entrances really isn't hard. (3/n)
Spice warning:🌶️🌶️🌶️
July 25, 2025 at 3:37 PM
Claims/implications that Iran may struggle to recover the highly enriched uranium that is probably sitting underground at Esfahan are just silly.
Digging debris out of tunnel entrances really isn't hard. (3/n)
Spice warning:🌶️🌶️🌶️
Digging debris out of tunnel entrances really isn't hard. (3/n)
Spice warning:🌶️🌶️🌶️
Recognizing this, U.S. officials have basically said, "we don't care if Iran has HEU. We destroyed its facility to produce uranium metal, without which its HEU is useless."
lol.
(8/n)
lol.
(8/n)
July 21, 2025 at 2:15 PM
Recognizing this, U.S. officials have basically said, "we don't care if Iran has HEU. We destroyed its facility to produce uranium metal, without which its HEU is useless."
lol.
(8/n)
lol.
(8/n)
Moreover, this material is not buried under rubble. The tunnels at Isfahan were not collapsed (too deep) so the HEU will be just fine.
That said, the U.S. may have attacked the tunnel entrances, which does raise questions about the material's accessibility. (4/n)
That said, the U.S. may have attacked the tunnel entrances, which does raise questions about the material's accessibility. (4/n)
July 21, 2025 at 2:11 PM
Moreover, this material is not buried under rubble. The tunnels at Isfahan were not collapsed (too deep) so the HEU will be just fine.
That said, the U.S. may have attacked the tunnel entrances, which does raise questions about the material's accessibility. (4/n)
That said, the U.S. may have attacked the tunnel entrances, which does raise questions about the material's accessibility. (4/n)
Attempts to play down the survival of most or all of Iran's HEU are comical.
It may be true that "only" the HEU at Isfahan is accessible--but that's almost all of it! (3/n)
It may be true that "only" the HEU at Isfahan is accessible--but that's almost all of it! (3/n)
July 21, 2025 at 2:11 PM
Attempts to play down the survival of most or all of Iran's HEU are comical.
It may be true that "only" the HEU at Isfahan is accessible--but that's almost all of it! (3/n)
It may be true that "only" the HEU at Isfahan is accessible--but that's almost all of it! (3/n)
U.S. officials continue to argue that it would take Iran years to rebuild the facilities that were hit. That seems right to me.
But a key question is this: How long would it take Iran to build the bomb? (2/n)
But a key question is this: How long would it take Iran to build the bomb? (2/n)
July 21, 2025 at 2:10 PM
U.S. officials continue to argue that it would take Iran years to rebuild the facilities that were hit. That seems right to me.
But a key question is this: How long would it take Iran to build the bomb? (2/n)
But a key question is this: How long would it take Iran to build the bomb? (2/n)
Still, at least anonymous sources are now being honest about the real policy, even if the odds of success are not good.
July 11, 2025 at 3:19 PM
Still, at least anonymous sources are now being honest about the real policy, even if the odds of success are not good.
I can think of no reason at all why Iranian leaders won’t jump at the chance to follow the “Libya model.”
Can you, Muammar?
Can you, Muammar?
July 11, 2025 at 3:14 PM
I can think of no reason at all why Iranian leaders won’t jump at the chance to follow the “Libya model.”
Can you, Muammar?
Can you, Muammar?
It'd be a pretty catastrophic outcome *IF* the attacks on Fordow failed to destroy centrifuges and they can be put back into service. I'm not claiming this is the case, but U.S. officials seem to be hinting it's a possibility. (1/n)
@hugolowell.bsky.social
@hugolowell.bsky.social
July 10, 2025 at 6:43 PM
It'd be a pretty catastrophic outcome *IF* the attacks on Fordow failed to destroy centrifuges and they can be put back into service. I'm not claiming this is the case, but U.S. officials seem to be hinting it's a possibility. (1/n)
@hugolowell.bsky.social
@hugolowell.bsky.social
Alliance management recommendations
The U.S. should also try to rebuild its relationships with allies but without allowing assurance to practically dictate U.S. force requirements. To this end it should: (9/n)
The U.S. should also try to rebuild its relationships with allies but without allowing assurance to practically dictate U.S. force requirements. To this end it should: (9/n)
July 9, 2025 at 2:41 PM
Alliance management recommendations
The U.S. should also try to rebuild its relationships with allies but without allowing assurance to practically dictate U.S. force requirements. To this end it should: (9/n)
The U.S. should also try to rebuild its relationships with allies but without allowing assurance to practically dictate U.S. force requirements. To this end it should: (9/n)
Nuclear strategy recommendations
Implementing a strategy of optimal deterrence should involve: (8/n)
Implementing a strategy of optimal deterrence should involve: (8/n)
July 9, 2025 at 2:41 PM
Nuclear strategy recommendations
Implementing a strategy of optimal deterrence should involve: (8/n)
Implementing a strategy of optimal deterrence should involve: (8/n)
A better targeting policy is to focus *exclusively* on conventional military forces and war-supporting industry (CMI) and not target nuclear forces.
The 👏 U.S. 👏 already 👏 targets 👏 CMI 👏 assets 👏and 👏does 👏 NOT👏 consider 👏 them 👏 countervalue👏 targets. 👏 (7/n)
The 👏 U.S. 👏 already 👏 targets 👏 CMI 👏 assets 👏and 👏does 👏 NOT👏 consider 👏 them 👏 countervalue👏 targets. 👏 (7/n)
July 9, 2025 at 2:40 PM
A better targeting policy is to focus *exclusively* on conventional military forces and war-supporting industry (CMI) and not target nuclear forces.
The 👏 U.S. 👏 already 👏 targets 👏 CMI 👏 assets 👏and 👏does 👏 NOT👏 consider 👏 them 👏 countervalue👏 targets. 👏 (7/n)
The 👏 U.S. 👏 already 👏 targets 👏 CMI 👏 assets 👏and 👏does 👏 NOT👏 consider 👏 them 👏 countervalue👏 targets. 👏 (7/n)
Allies--who the U.S. should value!--would object to any change in nuclear strategy. But the reality is that their concerns stem primarily from Washington's dismissal of their interests and will not actually be addressed by more nukes. (6/n)
Warning: 🌶️🌶️🌶️🌶️🌶️
Warning: 🌶️🌶️🌶️🌶️🌶️
July 9, 2025 at 2:40 PM
Allies--who the U.S. should value!--would object to any change in nuclear strategy. But the reality is that their concerns stem primarily from Washington's dismissal of their interests and will not actually be addressed by more nukes. (6/n)
Warning: 🌶️🌶️🌶️🌶️🌶️
Warning: 🌶️🌶️🌶️🌶️🌶️