"For people not committed to Donald Trump already, he did become presidential tonight. And I think we'll see that reflected in high approval ratings," said Senate Majority Leader Mitch McConnell, who decried Trump's Twitter tirades a little more than a week ago.
"It was an inspirational speech, widely applauded, as you can imagine, on our side, but greeted with a lot more applause and respect on the other side than I would have anticipated," the Kentucky Republican told CNN's Wolf Blitzer.
Behind the scenes, Republican lawmakers expressed relief that Trump did not go overboard in his speech. It was a far cry from his inaugural address, where he decried the "carnage" he said has beset America. Instead, Trump used a more traditional political tactic of painting a picture of that "carnage" -- talking about murders in Chicago and telling the personal stories of people whose family members were killed by undocumented immigrants.
Even Democratic lawmakers said Trump sounded more presidential Tuesday night in his first joint address to Congress -- while acknowledging it offered little in new details and may not have swayed any votes he'll need to approve reform efforts for health care or immigration or a $1 trillion infrastructure package.
"It sounded like the Donald Trump who is maturing into president," said Sen. Joe Manchin, a moderate Democrat from West Virginia who White House leaders have identified as an important target for many of their top priorities. And Manchin suggested Tuesday night he'd be willing to work with the White House on any immigration reform, saying, "I'm happy to work with him."
"That was the best speech Trump has ever given," said another Democratic senator, who acknowledged Trump's controlled demeanor would make it harder for Democrats to fight him if he can keep it up.
House Majority Leader Kevin McCarthy, a California Republican who has developed a close relationship with the Trump administration, appeared ecstatic about Trump's performance.
"I thought it was the best speech I've heard him give. And like anything else, when you get into a job and you do it for a while, you get better at it, and I think he's improving every single day," McCarthy told reporters gathered outside the House chambers after Trump's speech.
Trump's style Tuesday was far different than the fly-by-the-seat-of-his-pants approach some members of Congress have come to expect. Instead of talking about his electoral victory or voter fraud, Trump sought unity. Instead of calling out political enemies from the bully pulpit, Trump asked for Republicans and Democrats to come together as millions of Americans watched, with Speaker of the House Paul Ryan and the American flag draped behind him.
"Recent threats targeting Jewish Community Centers and vandalism of Jewish cemeteries, as well as last week's shooting in Kansas City, remind us that while we may be a nation divided on policies, we are a country that stands united in condemning hate and evil in all its very ugly forms," Trump said.
But Democrats still found plenty to fight against in Trump's first address to Congress. Some Democrats booed Trump as he called for a special force that would target undocumented immigrants who commit violent crimes. And one Democrat yelled, as Trump said Republicans should support health coverage for preexisting conditions: "That's Obamacare!"
Senate Democratic Leader Chuck Schumer told CNN's Blitzer it was "another one of his speeches where he talks like a populist, but the way he's been governing is the opposite -- governing from the hard right."
"The American people don't want a speech, they heard a lot of those, they want action. And the action he's giving them is disjointed -- he doesn't know how to really run a government," Schumer said.
Sen. Bernie Sanders, who ran in the Democratic presidential primary last year, used Twitter to highlight policies Trump implemented, contrasting them with the words in his speech.
"When Trump said we need to promote clean air and clean water, I had a hard time not laughing. Today he rolled back clean water rules," the Vermont senator tweeted.