"If Republicans had won Missouri and Indiana, they would have a larger majority and more margin for passing big pieces of legislation," said Nathan Gonzales, editor of Inside Elections, a nonpartisan campaign tracker. "Elections to the U.S. Senate have repercussions for at least six years. It is not just a fleeting issue."
"By the numbers we're still below the historical average, so until we get close to exceeding that number, it's tough to draw a grander conclusion. At an individual level, I think these retirements are based on a number of factors. I think it's rare a member retires because of one thing," Nathan Gonzales, editor of Inside Elections, said.