On Friday, President Trump officially used the Defense Production Act to force General Motors to make ventilators.

The move came after days of confusion where the President often said a different thing each day about whether the law had been “invoked.” Below is a timeline of his comments.

Last Wednesday, March 18, President Trump walked into the White House briefing room at 12:06 pm with a significant announcement.

“We'll be invoking the Defense Production Act, just in case we need it. In other words, I think you all know what it is, and it can do a lot of good things if we need it. And we will – we will have it all completed, signing it in just a little while. Right after I'm finished with this conference, I'll be signing it. It's prepared to go. So we will be invoking the Defense Production Act.”

Hours later, he seemed to backtrack in a tweet about whether the law, which gives him the ability to compel companies to manufacture critically needed items in times of national need, had actually been invoked.

The next day, March 19, he clarified a bit during the daily coronavirus task force briefing.

Q: Mr. President, if I could, a question for you and then a question for Dr. Hahn. You “enabled” – I guess, is probably the best way to put it – the Defense Production Act yesterday, but you didn’t pull the trigger on it.

THE PRESIDENT: No, because we hope we're not going to need that.

Later in the briefing, he added this:

Q: Under what conditions would you put the Defense Production Act into action?

THE PRESIDENT: Well, if we were desperately in need of something – and we, frankly, will know about that very shortly. We want to be ahead of – we don't want to do it as it happens but before it happens. We're going to know a lot over the next two or three days. We'll know a lot.

The next morning, Senate Minority Leader Chuck Schumer had a call with Trump and asked him to invoke the act. Schumer’s spokesman later told reporters, using the acronym for President of the United States, that "POTUS told Schumer he would, and then POTUS yelled to someone in his office to do it now."

At the daily briefing later that day, on March 20, Trump was again saying he had “invoked” the act.

Q: You had a call with Senator Schumer. He says you've now agreed to invoke the Defense Production Act to actually make those medical supplies that hospitals say are in severe shortage. So two questions: Is that what you're doing now?

THE PRESIDENT: It is. I did it yesterday. We invoked it, I think, the day before we signed it – the evening of the day before – and invoked it yesterday. We have a lot of people working very hard to do ventilators and various other things. Yes.

The next day, on March 21, Trump clarified again that the White House had not actually compelled any companies using the act.

Q: One of the things we're hearing from governors: They can't find supplies and prices have gone up. So you've talked about the act, sir, but you have not yet compelled any companies. Why not?

THE PRESIDENT: Because we have so many companies making so many products – every product that you mentioned, plus ventilators and everything else. We have car companies – without having to use the act. If I don't have to use – specifically, we have the act to use, in case we need it. But we have so many things being made right now by so many – they've just stepped up.

A few days later, on March 23, he said he invoked the act in regard to vital medical equipment.

Earlier today, I signed an executive order invoking presidential authority under Section 4512 of the Defense Production Act to prohibit the hoarding of vital medical equipment and supplies such as hand sanitizers, face masks, and personal protective equipment.

The next day, he tweeted that that act was in “full force, but haven’t had to use it.”

By March 25, he was describing it as a “negotiating tool” at a White House briefing.

I spoke to the governor – Governor Cuomo – last night and this morning, and he mentioned that, in his remarks, that he's using the – that we are using – and I think he feels, because he understands negotiation – he thinks we're using very appropriately the Defense Production Act. And we are. We're using it where needed. It's a great point of leverage; it's a great negotiating tool.

The next day, March 26, he repeated, saying “We use it as leverage.”

$1 billion for Defense Production Act procurement. We are, as you know, using the Act, but we use it only when necessary. We use it as leverage. We generally don't have to use it to accomplish what we want to accomplish.

On March 27 Trump repeatedly tweeted at General Motors and again suggested he might invoke the act.

Trump’s attacks come as GM and Ford both announced this week that they are working with companies to help boost ventilator production. And soon after Trump’s first tweet, GM and Ventec announced they’ll build ventilators at the automaker’s parts plant in Indiana. GM sent Yahoo Finance this statement:

Ventec Life Systems and General Motors have been working around the clock to implement plans to build more critical care ventilators. With GM’s support, Ventec is now planning exponentially higher ventilator production as fast as possible.

On March 27, hours after back ad forth with GM, the White House sent official notice that the President was “directing the Secretary of Health and Human Services to use any and all authority available under the Defense Production Act to require General Motors to accept, perform, and prioritize Federal contracts for ventilators.”

It was the first official use of the act, 9 days after Trump first said he was invoking it. The White House statement said that negotiations had been ongoing with GM on supplying ventilators but the fight against coronavirus was too urgent and “GM was wasting time.”

This story has been updated.

Ben Werschkul is a producer for Yahoo Finance in Washington, DC.

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