Congress will return from its August recess on Tuesday, September 8 and will face a number of crucial fiscal deadlines.  Among the most important are keeping the government open amid fierce disagreement over spending caps put in place by the so-called 2011 sequester. Finding a long-term way to fund highway and transit projects and lifting the debt ceiling before default are also important issues that need to be delt with once Congress is back in Washington. Added to the mix is a vote on the Iran nuclear deal, hosting a papal visit, and a September calendar shortened due to religious holidays.

“Each side will have to give some things they don’t want to give and we’ll get to an agreement,” Senate Majority Leader Mitch McConnell (R-KY) said on government spending. Republican leaders have already conceded they cannot wrap up the appropriations work before the end of the fiscal year on September 30 and will need to enact a stop-gap funding bill, or continuing resolution (CR).

What follows is a list of looming deadlines and the challenges as reported in the The Washington Post.

September 30: End of the fiscal year and the deadline for funding the government

Democrats say they want a deal that raises spending caps for both domestic and defense programs and in the Senate they have successfully blocked consideration of appropriations bills as they try to force Republicans to  renegotiate their position.  House and Senate GOP leaders have largely ignored their demands and have instead focused on trying to make good on their vow to consider each of the 12 annual spending bills through regular order. But filibusters in the Senate and controversy in the House over amendments concerning the display of Confederate flags have left both chambers far short of that goal with the end of the fiscal year quickly approaching.

Now the question is when negotiations will begin in earnest.

The first step toward some kind of resolution will have to take place immediately when Congress returns, as the new fiscal year ends September 30. McConnell has not publicly said if he will support a short-term bill but he is promising there will be no shutdown. “I can’t tell you what will finally end up in or out of a government funding bill, but I can tell you, without fear of contradiction, there will be no government shutdown,” McConnell said. Even a straightforward CR may not be easy to pass.

Then leaders have to contend with the calendar.

Congress is scheduled to be working for just 12 days before the September 30 deadline. That calendar includes several shortened days at the beginning and the end of the week, several days off in observance of Rosh Hashanah and Yom Kippur and a day devoted to the September 24 visit from Pope Francis.

End of October: When the Treasury Department estimates the government will hit its debt limit

The deadline for increasing the borrowing limit is always a moving target, but Treasury Secretary Jack Lew warned Congress in July that they will have to act before the end of October. Congress has had to address the debt limit seven times since 2010, including the 2013 battle that ultimately led to the government shutdown. Several of the hard-line conservatives who fought against raising the debt ceiling two years ago are now running for president and have already begun stirring controversy in the Senate.

All eyes will be on Ted Cruz (R-TX), Rand Paul (R-KY), and Marco Rubio (R-FL) as the deadline nears. Cruz filibustered the last debt limit hike in 2014 but neither he nor his fellow presidential contenders have weighed in on this year’s pending deadline. A short-term extension is not out of the picture. But lawmakers have been largely silent on a path forward for increasing the debt limit.

October 29: Funding for the Highway Trust Fund expires

At the end of July, Congress successfully patched the federal highway trust fund through October 29. Leaders in both chambers say this should buy them time to come up with a long-term funding deal, but it is not clear how that would happen given their differences. The Senate already passed a three-year highway bill but the House refused to consider the legislation over funding objections. Instead, House Transportation Committee Chairman Bill Shuster (R-PA) said that the House will work on a long-term bill that could be considered this fall in conference with the Senate. Lawmakers are expected to take up that work quickly in September but there is a short timeframe for negotiations. That is why some are already quietly discussing another short-term extension.

At this point, December is expected to be relatively quiet for Congress. But that could change dramatically if leaders land on short-term solutions to the fall deadlines, creating the environment for a big year-end fiscal fireworks.

The only deadline on the calendar now is a year-end vote to extend dozens of expired and expiring tax breaks known as the extenders. The well-loved tax breaks have previously created a legislative headache amid debates over how much they would add to the deficit, but the Senate Finance Committee recently passed legislation to extend the provisions without much controversy. It is possible those tax breaks could cruise through Congress sometime before the end of the year. But the discussion will be a lot more complicated and difficult if the debate gets tied to any of the other must-pass legislation.