With shutdown looming, Trump is tweeting out demands. Will he stick by them?

"I also protect myself by being flexible. I never get too attached to one deal or one approach."

Those words from Donald Trump's The Art of The Deal may be giving congressional Republicans some hope this week.

That's because Congress is facing a midnight Friday deadline to pass legislation to keep the federal government fully open -- or face a partial government shutdown precisely on President Trump's 100th day in office.

Government shutdowns are not unheard of, but those in recent memory came when power was divided, not when one party controled both chambers of Congress and the White House. Republicans are aware that their party generally gets blamed for government shutdowns, even if it doesn't necessarily pay the price at the ballot box.

Republicans held the House and won control of the Senate in 2014 -- a year after the public put much of the blame on their party for the shutdown in late 2013.

But on the heels of the failed GOP health care effort, Republicans are hoping to avoid an embarrassing episode as they try to prove they are a party that can govern effectively.

"The president is working hard to keep the government open and addressing various issues," Treasury Secretary Steven Mnuchin told reporters Monday.

Trump has several demands that could complicate hopes on Capitol Hill for a "clean bill" -- one without controversial provisions. House Speaker Paul Ryan has vowed to avoid a shutdown, and told lawmakers on a conference call over the weekend, "Wherever we land will be a product the president can and will support."

Senate Democratic leader Chuck Schumer said over the weekend that a deal could get done, if the president stays out of it and lets Congress negotiate among itself. He called Trump's demands "the only fly in the ointment."

Trump has made several of his demands known on Twitter. So what does he want?

1) Wall funding

Congressional leaders have been saying for months that they know they will have to put up money for Trump's request to build a wall on the border with Mexico. Senate Majority Leader Mitch McConnell was asked whether Mexico would pay and had a simple answer: "Uh, no."

But they've also maintained it would be a separate issue from keeping the government open.

"Once the government is up and running, and stays open and running, then we have to fight this out over the next year," Rep. Peter King, R-N.Y., told Fox News Sunday.

Trump's team has been sending mixed messages. Homeland Security Secretary John Kelly said on CNN, "I would expect he'll be insistent on the funding." But in an appearance on NBC's Meet The Press, Trump's chief of staff Reince Priebus refused to say whether the president would veto a bill without border funding.

The Associated Press reported Monday evening that Trump told a group of conservative reporters he'd be willing to let the wall funding slide to September.

Democrats have been saying that wall funding is a non-starter, with public opinion on their side. A Washington Post-ABC News poll released over the weekend showed the following: "Sixty percent of adults oppose building a wall along the U.S.-Mexico border, while 37 percent support it. Of these respondents, 47 percent are strongly against it."

2) Increased military spending

For all the goals Trump won't accomplish by his 100th day in office, he may feel more bullish about getting a boost in military spending included in the spending bill. It's seen as one of the controversial sticking points that can hold things up, but Trump has cover from some critics.

White House press secretary Sean Spicer said it was the primary goal in spending negotiations on Monday.

Sen. John McCain, R-Ariz., said in March that he would not vote for a bill that didn't increase military spending above current levels. He told CNN that doing so "destroys the ability of the military to defend this nation, and it puts the lives of the men and women in the military at risk."

Trump had dinner Monday night with McCain and Sen. Lindsey Graham, R-S.C., another Trump critic in the GOP, who is in lock step with McCain on defense issues.

Defense spending also lacks the the quality of being a hallmark Trump issue like the wall, so Democrats may not be as energized in opposing such an increase. Blocking wall funding would be a bigger win for them.

3) Health care

Trump is pushing a revival of GOP efforts to repeal and replace the Affordable Care Act, which imploded last month. He has been noncommittal as to whether a vote would need to happen this week and possibly tangle up passing a bill to keep the government open.

But with the Affordable Care Act in place, the president has been hinting at using the healthcare program as a bargaining chip with Democrats. The administration could drop subsidies to help reduce out-of-pocket costs for low-income Americans, which could destabilize the health-insurance market.

White House budget director Mick Mulvaney told Bloomberg that the administration had made an offer to Democrats to maintain a dollar in subsidies for every dollar of wall funding they are willing to provide.

Trump has said Democrats will take the heat if Obamacare collapses, but blaming the opposition for the consequences of such public threats from the president himself might prove challenging.

Democrats have already been turning it back on Trump.

"The White House gambit to hold hostage health care for millions of Americans, in order to force American taxpayers to foot the bill for a wall that the president said would be paid for by Mexico is a complete nonstarter," Schumer spokesman Matt House said.

Trump may be fixated on the bigger goal here, though. On Monday, he warned that Obamacare is already failing, something that the Congressional Budget Office says isn't true, and promised that the GOP will fix it with its own plan.

Trump has emphasized his flexibility, but on the health care bill he demonstrated a willingness to walk away from the table in the midst of a negotiation.

With the prospect of another legislative defeat on the eve of his 100th day as president, Trump might be keeping in mind another passage from The Art of The Deal:

"You can create excitement, you can do wonderful promotion and get all kinds of press, and you can throw in a little hyperbole. But if you don't deliver the goods, people will eventually catch on."