Congress returns next week (September 8) from a five-week recess facing a vote on the Iran nuclear deal and another threat of a government shutdown.

The most pressing, time-sensitive issue is legislation to approve or disapprove the Iran nuclear deal that was agreed to by the United States, Great Britain, France, Germany, Russia, China, and Iran in July. Both the House and Senate are expected to take up the deal when Congress returns next week, with the House voting by September 11.

The deal has been strongly opposed by congressional Republicans (who control both the House and Senate). Congress has until September 17th to act on the deal. If both the House and Senate pass a bill disapproving the deal as most observers expect, the president is sure to veto it.

In the House 144 votes are needed to override a veto, probably more than the Democrats could muster, although Democrat leaders are expressing some confidence that they might be able to garner the votes. In the Senate a veto is sure to be sustained as 38 Senate Democrats have declared their support of the deal, more than the 34 required. However, if 41 Senate Democrats support the deal, they will be able to stop the bill from coming to a vote in the Senate, which would negate the need for a presidential veto to move forward with the provisions of the deal.

And then, of course, there is the matter of funding the government for FY2016. When Congress returns there will be only about three weeks (including about 10 legislative days) before the beginning of FY2016. As Congress has completed none of the 12 appropriations bills (the House passed all 12 bills, but the Senate has passed none), Members and Senators will face a crucial decision: pass a Continuing Resolution (CR) to allow agencies to continue operating or force a government shutdown.

House and Senate Republican leaders have expressed no desire to shut down the government. To avoid that at least in the short-term, they will have to agree on a CR of some length. However, the rise of sentiment to defund Planned Parenthood among many Republicans casts at least some doubt on Speaker John Boehner’s (R-OH) ability to move a CR in the House without much controversy. If Boehner cannot come up with enough Republican votes to pass a CR he will have to work with Democrats to make up the difference to avoid a shutdown.

Even so, if the House and Senate were to pass a CR that defunds Planned Parenthood, the president would surely veto it. This would push the government to the brink of shutdown, an outcome only a few seem to be willing to accept, yet is still possible.