The five issues that will decide the midterm elections

There are less than two months left before the midterm elections.

Lately, Democrats have become more hopeful and Republicans more nervous as the polling lead the GOP enjoyed earlier in the year has eroded.

The battle for the Senate looks, for now, to be balanced on a knife-edge, even as the GOP remains favored to take over the House.

Candidates and local issues will clearly be vital in many races. But this is a national election too.

Here are the five biggest issues that will determine the outcome.