Trump gives Congress an olive branch with tax pitch, but will it last?

When President Trump traveled to Missouri on Wednesday to make his pitch for tax code overhaul, it was a more conventional — even conciliatory — chief executive who showed up.

Trump expressed optimism that he could work together with the legislative branch to pass something meaningful — although as NPR's Scott Horsley noted, the president offered scant specifics about what that legislation would be.

"So this is our once-in-a-generation opportunity to deliver real tax reform for everyday, hardworking Americans," Trump said. "And I am fully committed to working with Congress to get this job done, and I don't want to be disappointed by Congress. Do you understand me? You understand."

"I think Congress is going to make a comeback. I hope so," the president added. "Tell you what, the United States is counting on it."

Trump has been smarting from failed efforts to repeal and replace the Affordable Care Act in July, which led to very public airing of grievances against Senate Majority Leader Mitch McConnell, R-Ky.

And, as the president has seen his own approval ratings take a nosedive, the fact remains that Congress is even more unpopular than he is. In Missouri, he appeared to allude to those numbers, but didn't gloat.

GOP leaders sounded receptive to Trump's tax pitch and underscored they would work together.

"Right now, our tax code is burdensome, incomprehensible, and puts American businesses at a severe disadvantage on the world stage. ... That's why we are committed to reforming the tax code and why President Trump reiterated his commitment today in Missouri. We are united in our determination to get this done," House Speaker Paul Ryan, R-Wis., said in a statement.

McConnell wrote an editorial Wednesday morning pledging to "continue to work with my colleagues in Congress and the Administration to help middle class families and put the economy on the right track."

Trump struck a more upbeat — and on-message — tone than he has as of late. At a campaign rally last week in Arizona, Trump was all over the place. He not only defended his controversial comments about blame on "both sides" in the wake of racist violence in Charlottesville, Va., he also drew a line in the sand over funding his Southern border wall.

"If we have to close down the government," Trump said, "we're building that wall."

In that speech, Trump took more aim at Republican than he did at Democrats. He called out the states' two GOP senators: Jeff Flake, who faces a primary threat and a general election fight in 2018 and has been critical of the president, and John McCain, whose no vote prevented GOP health care efforts from moving forward. In the past, Trump has also criticized Nevada Sen. Dean Heller, who is the most vulnerable GOP senator up in 2018.

But in pitching tax overhaul on Wednesday — likely to the relief of Senate Republican strategists — Trump finally put pressure on a Democrat.

"And your senator, Claire McCaskill, she must do this for you. And if she doesn't do it for you, you have to vote her out of office," Trump told Missourians. "She's got to make that commitment. She's gotta make that commitment. If she doesn't do it ... you just can't do this anymore with the obstruction and the obstructionists."

His remarks were clearer than his tweet over the weekend, in which he spent the limited characters touting his 2016 electoral win in the Show Me State instead of spelling out McCaskill's name or the word "Senate."

Normally, a Republican president calling out a vulnerable Democratic senator who is up for re-election wouldn't be news. But the simple fact that Trump was able to stay on the party message and target a Democratic incumbent — in a state he carried last November — is noteworthy.

Helpful for the party or not, Politico reports that Trump's comments about McCaskill could present a legal problem — that is, if the words were written by White House aides, who are prohibited from mixing partisan politics and official business. (The president, who may have ad-libbed, is not subject to the Hatch Act.)

Whether Trump can stay on message — and out of tussles with fellow Republicans — as Congress returns from August recess and gets back to legislative business next week is up in the air. Wednesday was an official White House event, and it's his campaign rallies like the one in Arizona that have often served to strain relations with the lawmakers he needs on his side for a legislative victory.

On Wednesday, it was President Trump on stage, making a pitch to lawmakers. But on the campaign trail he loves so dearly, it's the free-wheeling Candidate Trump who wants to please his base at seemingly any cost.