October surprise? 5 things that could rock the midterms

From the growing caravan of migrants making its way toward America's southern border to a pledge of new tax cuts for middle-income Americans, the midterm season could yet hold a few twists and turns between now and Election Day.

The Nov. 6 elections are widely seen as a referendum on the Trump administration and Republican policies pushed in the past two years. Democrats hope to take control of the House and Senate, where Republicans hold a narrow lead.

But a series of developments could tilt the final outcome. Thousands of migrants are heading to the U.S. border seeking asylum, tensions with multiple foreign nations seem ready to boil over and Special Counsel Robert Mueller’s investigation into Russian interference in the 2016 presidential election is nearing a close.