In the midst of rising tensions with North Korea — with the prospect of war with a nuclear-armed power being widely considered in the US for the first time since the Cold War — President Donald Trump decided that Wednesday morning would be a good time to tweet this:

My first order as President was to renovate and modernize our nuclear arsenal. It is now far stronger and more powerful than ever before.... — Donald J. Trump (@realDonaldTrump) August 9, 2017

...Hopefully we will never have to use this power, but there will never be a time that we are not the most powerful nation in the world! — Donald J. Trump (@realDonaldTrump) August 9, 2017

Not exactly the best way to tamp down on tensions with the North.

But the statement is also kind of confusing: What does Trump mean when he says “renovate and modernize” the nuclear arsenal?

The president is actually referencing a real issue here: The US nuclear arsenal is aging and in need of maintenance. Generally speaking, you don’t want weapons that can destroy the world to be in subpar shape.

But Trump’s claim that he ordered the US government “to renovate and modernize our nuclear arsenal” is completely false. He has done no such thing. And America’s arsenal is not currently “far stronger and more powerful than ever before.” Trump has more or less continued the nuclear maintenance efforts begun by President Obama, which will take years to complete.

Trump’s statement is, as former State Department adviser for nuclear policy Alexandra Bell puts it, “a total lie.”

What’s worse, it’s a lie with consequences. The last thing you want to do in the midst of a crisis with North Korea, experts say, is send signals that you’re prepared to launch a strike against the North. And that’s unmistakably the message these tweets send.

What Trump gets wrong about nuclear modernization

The US nuclear arsenal is based on what’s called “the nuclear triad”: land-based intercontinental ballistic missiles (ICBMs), submarines equipped with nuclear missiles, and nuclear bombs that can be dropped by bombers. The reason for keeping all three of these kinds of weapons is to ensure that they can be delivered in a crisis: If an enemy somehow managed to neutralize, say, all of America’s land-based ICBMs in a preemptive nuclear strike, the US would still be able to hit them back with bombs dropped from the air and missiles launched from subs.

This system obviously doesn’t work if all three legs of the triad aren’t functioning. And right now, they’re not in tip-top shape.

Take the ICBMs, for example. In 2014, the Associated Press did a deep investigative dive into the state of the force — and what they found was disturbing. My colleague Yochi Dreazen summarizes the two main highlights:

The first was that Air Force personnel at a base in Montana that stored nuclear-tipped intercontinental missiles had been routinely cheating on proficiency tests, meaning they might not have actually had the skills needed to keep the deadly weapons functioning safely. The commander of the base resigned, and nine others were fired for their role in the scandal, which implicated more than 100 officers. The second, first reported by the AP, was that Air Force security personnel at Malmstrom had been unable to properly respond to a drill simulating the capture of a nuclear silo by a hostile force. An internal Air Force report said the security team’s inability to regain control of the silo quickly was “a critical deficiency.”

And there are major technical problems in addition to the poor training highlighted by the AP. The 12 Ohio-class nuclear-armed submarines that make up one leg of the triad first came into use in 1981, and they only function effectively for 42 years. That means the US will need to begin either refurbishing or replacing its nuclear submarines within the next decade.

The Obama administration worked for years to try to fix this problem, culminating in a plan to spend roughly $1 trillion over 30 years on nuclear modernization. The Trump administration inherited this plan and basically did nothing to change it.

“Trump's first budget proposal largely continues Obama’s plans,” explains Kingston Reif, an expert on America’s nuclear arsenal at the Arms Control Association. “[And it] won't take effect until October 1 at the earliest.”

The most Trump has done on nuclear policy was in a January 27 executive order, where he instructed Secretary of Defense James Mattis to conduct a review of America’s overall nuclear stance. This was not, as Trump suggested, his first executive order — he had issued at least four before it.

What’s more, this review is still in process. It has yet to produce any actual recommendations for changing course from Obama’s nuclear policy, let alone led to any concrete changes in the US nuclear arsenal. Trump’s claim to have made America’s nukes “far stronger and more powerful” is just completely made up.

“There is no demonstrable difference between our nuclear arsenal now and our nuclear arsenal on Jan 19,” Bell tweets.

Saber rattling with North Korea is a bad idea

Here’s the other problem with Trump’s tweets: They send exactly the wrong message to North Korea.

Trump’s tweets come on the heels of his comments about North Korea on Tuesday, in which he threatened to respond to the North’s provocations with “fire and fury like the world has never seen.” By talking about how strong America’s nukes are the next day, he’s clearly sending a message to the North that the use of America’s nuclear weapons is on his mind. Reif calls this “reckless nuclear flaunting,” and that seems exactly right.

This kind of rhetoric raises the level of overall tensions, signaling — rightly or wrongly — that the Trump administration may be more belligerent than it was in the past. And experts say that scaring North Korea is not likely to bring it in line. It’s more likely, in fact, to lead them to take their own aggressive steps.

“The situation is not going to become safer by threatening North Korea,” Jenny Town, the assistant director of the US-Korea Institute, tells me. “It is only going to antagonize an already tense relationship, risking the safety of the United States and our allies in Asia, South Korea, and Japan by raising the potential for conflict — whether intentional or accidental.”

This is why Trump’s tweets are a problem. It’s not just that they’re wildly misleading about a vital issue, which would be bad enough. It’s that the president’s rhetoric is a primary way that North Korea understands American intentions. When Trump talks loosely and aggressively about the power of American nukes at a time of crisis with Pyongyang — a crisis partially created by his own comments — it fuels Kim Jong Un’s paranoia.

“His words could ... lead Pyongyang to miscalculate or believe it needs to act preemptively if it believes a US attack is imminent,” Laura Rosenberger, the former National Security Council director for Korea and China, told me after Trump’s “fire and fury” comments on Wednesday. “Those consequences could be catastrophic.”