President Trump and Senate Majority Leader Mitch McConnell faced reporters side by side on Monday amid the stagnation of the Republican congressional agenda and a looming civil war over Republican Senate candidates.

Both Trump and McConnell made clear that they would work to wave Steve Bannon, Trump's former chief strategist, off races where a contested GOP primary may yield a candidate who can't win in a general election. The two leaders — at odds for weeks over tactics, pace, and priorities — projected unity on agenda items from tax reform to healthcare, promising speedy results in the dwindling number of days left on the year's legislative calendar.

McConnell came to the White House at the president's invitation. Vice President Mike Pence, chief of staff John Kelly, and White House legislative director Marc Short had pressed for a public detente between Trump and McConnell, a Republican close to the White House told the Washington Examiner.

"[T]this type of change tends to happen from the inside and not from outside pressure from the Senate," the Republican said. "It occurred now in order to head off further erosion in the relationship between the White House and Senate Republicans after Trump attacked McConnell and [Sen. Bob] Corker repeatedly."

Trump's relationships with Republicans on Capitol Hill had frayed in recent weeks as a feud with Corker, a retiring Tennessee senator, spilled into the open and his legislative deals with top Democrats raised concerns among congressional conservatives.

His private meeting and public press conference with McConnell this week could alleviate fears within the party that the president could be looking to appease his base at the expense of GOP leaders, who he has blamed for delays in passing healthcare reform and tax cuts. But some Republican strategists predicted the truce will be temporary for two sides that have long harbored skepticism about the other.

"Their differences are never going to be quelled. McConnell is an institutionalist, and Trump is a shot against institutionalism," said Ford O'Connell, a GOP strategist.

O'Connell said the two likely came together this week because remaining opposed could sink both of their futures as elected officials.

"They may be strange bedfellows, but their political livelihoods are basically intertwined," O'Connell said. "Their political livelihood rests with their ability to actually do things."

McConnell and Trump have clashed since the late summer over how and why longstanding Republican priorities, such as repealing Obamacare, languished in the upper chamber and dashed Trump's hopes of packing the early months of his presidency with action.

The Senate majority leader cited Trump's "excessive expectations" in early August as a factor in the president's disappointment over the collapse of healthcare negotiations.

Trump took to Twitter days later to ask why, after years of calling for the repeal of Obamacare, McConnell failed to produce a bill that did so even though such a measure passed the House.

Rumors of growing animosity between the two began to filter into headlines by late August, although both sides half-heartedly denied any rift between them.

Liz Mair, a Republican strategist who has long opposed Trump, suggested the display of solidarity between the president and McConnell on Monday could soon wither.

"My baseline assumption is that any ‘thaw' is a purely temporary thing at best, or at worst, the appearance of a reconciliation is being set up only for Trump to come out and trash McConnell again in short order," Mair said.

But the kind words Trump showered on McConnell during a Rose Garden appearance with his erstwhile enemy hinted at an alliance that could help Republicans move ahead on a tax reform plan that the White House would like to see passed by the end of the year, despite dissent within the party over raising deficits.

Some observers said the underlying relationship between Trump and McConnell was never as sour as the media depicted it, something the majority leader himself claimed in remarks at the White House on Monday.

"I believe that Trump and McConnell have a good relationship with an understanding that Trump has to criticize him on occasion to keep his base at bay," said Sean Noble, a Republican strategist.

Trump and McConnell pledged to protect some Republican lawmakers from the primary challenges Bannon has vowed to back in 2018. While Trump promised only to try to persuade Bannon — whom he described as a friend — to spare the "nice" senators, McConnell said he would shield his incumbents against primary challengers that could embarrass the party. The Kentucky senator cited Todd Akin, a Missouri Republican candidate from 2012 who lost what many believed to be a winnable Senate race, as an example of what can happen when unpredictable firebrands win GOP primaries.

Brad Blakeman, a Republican strategist, suggested both Trump and McConnell will need to produce the "big ticket" items they promised in 2016 in order to be successful in 2018.

"The president and the majority leader rise and fall with each other and their ability to lead and deliver. There is nothing President Trump likes more than ‘deliverables,'" Blakeman said. "And, success will bond these leaders together publicly and privately."