Amy Walter, Cook Political Report

The gap is six. As we crunch the numbers, count the money and consider the issues around Midterm 2014, six is the figure you may hear more than any other.Of course, that’s the number of seats separating Democrats and Republicans from Senate control. And with Health Care rollouts, government shutdowns, jobs, equality issues and more on voters' minds, the question is simple: Can Republicans win the six seat margin and take leadership of both houses for the first time since the 2006 midterms?One person doing the math and analyzing the races state by state: Amy Walters, National Editor of the must-read Cook Political Report.