Sen. Ruben Gallego, D-Ariz., a Marine combat veteran, slammed President Donald Trump on Thursday for his attacks against Democratic veterans who called for servicemembers to "refuse illegal orders," suggesting Trump was trying to distract from the Epstein files fallout and "doesn't understand" the military.

"He thinks the military is one of his personal little play toys ... he, for some reason, thinks that men and women upholding their oath is a contradiction to him as commander in chief - which, again, tells you he doesn't really understand his role," Gallego told ABC News.

Gallego, who did not take part in the video, said the Democrats were "trying to put out into the atmosphere to military personnel that, if you feel that there's something illegal, that you have a right to object. There's nothing that crazy. It's something that is entirely taught within all military forces."

Gallego said he is hearing "unease" from servicemembers about "what could happen" with future orders from the Trump administration, "not what's happening now."

--ABC News' Benjamin Siegel

The White House on Thursday expressed optimism after Army Secretary Daniel P. Driscoll met with Ukrainian President Volodymyr Zelenskyy to talk about a potential peace plan.

"I'm not going to litigate the details of this plan as it's ongoing and it's in flux. But the president supports this plan. It's a good plan for both Russia and Ukraine. And we believe that it should be acceptable to both sides. And we're working very hard to get it done," White House press secretary Karoline Leavitt said at her briefing.

Leavitt was asked about reports that the plan is more favorable to the Russians than Ukrainians.

"You've read reporting from one side of the war. And so I want you to understand that the administration has talked equally with both sides. You have seen President Trump engage directly with both President Putin and President Zelenskyy. Likewise, his national security team has as well. In fact, special envoy Witkoff and Secretary Rubio met with some of the Ukrainians just in the past week to discuss this very plan," Leavitt said.

White House press secretary Karoline Leavitt dismissed the idea that President Donald Trump's social media posts calling Democratic lawmakers "traitors" who should face the death penalty amounts to the political violence he's accused the "radical left" of partaking in.

"The president and the vice president, for that matter, have accused the other side of encouraging political violence. Isn't that exactly what the president is doing when he says that members of Congress should be killed?" a reporter asked Leavitt during Thursday's briefing.

"Why aren't you talking about what these members of Congress are doing to encourage and incite violence?" Leavitt responded. They are literally saying to 1.3 million active duty service members not to -- to defy the chain of command, not to follow lawful orders," Leavitt said.

Leavitt added, "To suggest and encourage that active-duty service members defy the chain of command is a very dangerous thing for sitting members of Congress to do, and they should be held accountable. And that's what the president wants to see."

When the reporter followed up that the video that prompted Trump's posts was about illegal orders, Leavitt said they're "suggesting" that Trump "has given illegal orders, which he has not."

White House press secretary Karoline Leavitt said details are being worked out for Friday's meeting between the president and New York City Mayor-elect Zohran Mamdani.

However, she did take a shot at the progressive democrat.

"It speaks volumes that tomorrow we have a communist coming to the White House," she said.

Mamdani has been a member of the Democratic Socialists group, which experts have argued are far from the authoritarian socialism practices of communist governments such as the Soviet Union and Cuba.

"I also think it speaks to the fact that President Trump is willing to meet with anyone, and talk to anyone, and to try to do what's right on behalf of the American people, whether they live in blue states or red states or blue cities," Leavitt added.