High stakes battles on nearly every facet of American government and President Donald J. Trump’s agenda come to a head in September, from the debt ceiling to government funding bills to healthcare and tax reform.

Each is likely to be fraught with perils to other areas of federal policy like immigration, trade, foreign policy, and more. The legislative battles looming next month, sources throughout Washington tell Breitbart News, will test President Trump’s and his congressional GOP leadership counterparts’ mettle alike–proving once and for all who’s in charge and whether they can govern.

“I think the stakes don’t get any higher than September 2017,” Tommy Binion, director of congressional and executive branch relations at the Heritage Foundation, told Breitbart News.

To date this year, Congress has lived up to its do-nothing reputation, with not-too-many major legislative accomplishments; Supreme Court Justice Neil Gorsuch’s confirmation, benefits for veterans, and various regulation rollbacks are perhaps the most notable exceptions. Trump has been busy chalking up administrative victories while Congress languishes, scoring achievements for his agenda across the government despite bureaucratic lethargy and pushback from career government workers comprising the administrative state.

But as summer turns to fall, the deadlock begins, forcing what seems like a “now or never” moment for congressional Republicans as they confront fights over funding the government and dealing with the debt ceiling–while aiming to take another shot at repealing Obamacare and kickstarting a tax code overhaul.

The “must-pass” spending bill will need to be shaped to please both conservatives in the House, Democrats in the Senate, and the president, who wants to see the border wall funded. And on the debt ceiling, conservatives in the House have made it clear that they won’t budge unless legislation includes spending reforms. Then there’s what Binion calls the “mega promises” made by the GOP and the Trump campaign as they rose to power in both chambers and at the White House — repealing and replacing Obamacare and a tax cut for Americans.

On health care, Congress and Trump could get help from someone who once faced these kind of legislative battles.

Former Pennsylvania Senator Rick Santorum told Breitbart News in an exclusive interview on Monday that he is working with a broad coalition of Republicans in both the House and Senate, along with several governors, to develop a new effort to repeal Obamacare. The effort is spooking Democrats and Obamacare protectors alike, with a former Obama administration official responsible for overseeing Obamacare saying it represents the biggest threat yet to Obamacare. But even the slightest screwup could derail the effort, as is what happened in several prior tries in both the House and Senate this year, given slim GOP majorities in both chambers of Congress, but especially the Senate.

That’s all not to mention the hot-button immigration issue, one that helped elect Trump but now could become a slap in the face to his base if the rumors are true that the president might use the Obama-era temporary amnesty program for illegal alien youth, or Deferred Action for Childhood Arrivals (DACA), as a bargaining chip to get the wall and other security apparatus he wants in place. Trump has himself not addressed DACA recently, but a deadline on the issue looms as well–forcing the administration’s hand in an already tumultuous month.

At a rally in Arizona on Tuesday night, Trump threw down the gauntlet when it came to probably the most concrete campaign promise in history–promising House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell that, on the spending bill, he would shut the government down if he did not get funding for a border wall.

“If we have to close down our government, we’re building the wall,” Trump said to the cheering crowd in Phoenix.

In fact, at least one prominent lawmaker said a lack of progress in September could lead to significant losses for Republicans on Capitol Hill if they can’t advance the president’s agenda now.

“Bottom line: if Paul Ryan and Mitch McConnell can get the president’s agenda done, they probably keep their jobs,” Rep. Mark Meadows (R-NC) and chairman of the House Freedom Caucus told The Hill.

“If Paul Ryan and Mitch McConnell can’t get the president’s agenda done, I don’t know that they get to keep theirs, nor do I know if I get to keep mine,” Meadows said. “We’ve got to deliver. It’s critically important we do that in a way that conservatives have long espoused.”

McConnell has been griping privately about Trump, per recent reports, further complicating matters. The New York Times reported on Tuesday that friction between the top senator and the president could be building to all out war. Alex Burns and Jonathan Martin wrote in the Times:

The relationship between President Trump and Senator Mitch McConnell, the majority leader, has disintegrated to the point that they have not spoken to each other in weeks, and Mr. McConnell has privately expressed uncertainty that Mr. Trump will be able to salvage his administration after a series of summer crises. What was once an uneasy governing alliance has curdled into a feud of mutual resentment and sometimes outright hostility, complicated by the position of Mr. McConnell’s wife, Elaine L. Chao, in Mr. Trump’s cabinet, according to more than a dozen people briefed on their imperiled partnership. Angry phone calls and private badmouthing have devolved into open conflict, with the president threatening to oppose Republican senators who cross him, and Mr. McConnell mobilizing to their defense.

Meanwhile, lawmakers and analysts acknowledge time is running out for Republicans and, moreover, for the leadership in Congress and on Pennsylvania Avenue.

“It’s past time to fulfill our campaign promises,” Rep. Jim Jordan (R-OH) told Breitbart News. “We need to repeal Obamacare, start working on tax reform, address our federal debt limit, and fund the government – among other things.”

It remains to be seen if the GOP can prove it can govern, Jordan said.

“Republicans control the House, the Senate, and the White House,” Jordan said. “We need to act boldly and secure our borders, move forward on the 2015 Obamacare repeal legislation that we’ve all agreed to previously, and lower tax rates for everyday Americans.”

“If we don’t fulfill our promises after voters gave us control of all of Washington, they will remember,” Jordan added.

Those close to leadership agree on the stakes in September. Rep. Kevin Brady (R-TX), chairman of the House Ways and Means Committee, said that Congress has to deliver “now.”

“It is crucial that Congress deliver on President Trump’s legislative priorities this year,” Brady told Breitbart News, adding that he has confidence in Trump’s ability to get tax and healthcare reform and border security done.

Saying that the legislative agenda involves “consequential issues,” Brady said the time has come for action.

“We have to deliver – and we have to deliver now,” Brady said.

But Rep. Diane Black (R-TN), chairman of the House Budget Committee and member of the House Ways and Means Committe, told Breitbart News that there has been some success already in the House, including the passage of the 2018 budget resolution — “the most conservative in 20 years” — that would “cut $200 billion in mandatory spending, reform the government, and fund some of our top conservative priorities like stronger border security, which has been a priority for this administration and my home state of Tennessee.”

“That’s what I’m focused on and that’s what I’ll be fighting for in September,” Black said.

Karlyn Bowman, senior fellow at the American Enterprise Institute on public opinion and polls, U.S. politics, and the media, told Breitbart News that September might not differ much for other months, given what’s been accomplished by the 115th Congress and the White House so far.

“I would have said it was the calm before the storm, but it hasn’t been very calm this summer,” Bowman said, but added urgency is needed.

“September will be important as there are few legislative days left and an enormous number of issues to address,” Bowman said. “The public has very low expectations for the president and Congress given what they’ve seen thus far,” Bowman said, and added that a government shutdown would “hurt all political actors.”