"Get ready Russia, because [missiles] will be coming, nice and new and 'smart!'" Trump said.
But giving the likes of Russia advance notice of what's coming is something the Old Trump would say is the opposite of "smart." He railed against President Obama doing it in 2016 and said early in his presidency that he wouldn't repeat those mistakes. He said doing so would only tip off the enemy, and he even said it specifically about Syria.
Here's what he tweeted in 2013:
He added in April 2017 in remarks about Syria. “One of the things I think you've noticed about me is: Militarily, I don't like to say where I'm going and what I'm doing. I'm not saying I'm doing anything one way or the other.”
“I don't want to telegraph what I'm doing, or what I'm thinking,” he said. “I'm not like other administrations, where they say we're going to do this in four weeks and that. It doesn't work that way.”
Trump has regularly talked about how the Obama administration previewed an attack on Mosul in Iraq for so long that the Islamic State fortified itself for the coming attack.
“I have often said that General MacArthur and General Patton would be in a state of shock if they were alive today to see the way President Obama and Hillary Clinton try to recklessly announce their every move before it happens — like they did in Iraq — so that the enemy can prepare and adapt,” Trump said in his big speech about fighting terrorism in August 2016.
While discussing that and North Korea at a February 2017 news conference, Trump said he would apply a different approach.
“I don't talk about military, and I don't talk about certain other things — you're going to be surprised to hear that,” he said. “And by the way, my whole campaign, I'd say that. So I don't have to tell you. I don't want to be one of these guys that say, 'Yes, here's what we're going to do.' I don't have to do that. I don't have to tell you what I'm going to do in North Korea.”
Trump does seem to have less concern about telegraphing troop withdrawals, calling for getting out of Iraq and Afghanistan repeatedly on the campaign trail. But now that he's president, he's in a position to make such withdrawals happen rather quickly. The 2016 Trump would probably argue that announcing you're getting out of Syria before you do it might signal to the Islamic State that it can just bide its time until the United States leaves and then it will have only “other people” to contend with.
And the 2016/17 Trump would surely argue against giving Russia a heads-up that bombs are coming Syria's way. In fact, that's pretty much exactly what Trump said would have made Patton and MacArthur roll over in their graves.