These four political problems could derail market

Social Security battleground

Donald Trump's raucous presidential campaign won't be the only thing lighting the political fires this fall.

A handful of significant deadlines and policy decisions loom for Washington and Wall Street that could bring volatility to the financial markets, though perhaps not on a fiscal cliff-type level.

Among the big events to remember:

1. The Iran nuclear agreement: Congress has 60 days to review the pact between the White House and Iran, and it could end up as an impasse wherein lawmakers pass a resolution rescinding the agreement that President Barack Obama vetoes.

Read More Lew: The high price of rejecting Iran deal

2. The end of the fiscal year: Sept. 30 concludes the budgetary cycle and could bring with it more of the same tango between the warring Washington parties. "There is a greater risk of a federal government shutdown from Oct. 1 than at any point since the last one occurred two years ago, though a shutdown this fall is not quite our base case," Goldman Sachs economist Alec Phillips said in a note.