The prospect of a Republican Senate majority relies more than ever on a strong showing at the top of the ticket by GOP presidential nominee Mitt Romney.
With less than eight weeks to go and both national party conventions complete, a path remains for the Republicans after several weeks of shifts in the Senate landscape. But for the GOP, it's now more akin to a game of hopscotch than a straight-line sprint to the majority.
It could require a leap over Missouri - once a virtual sure thing for the GOP - to Connecticut, where the Senate race appears closer than it ever was in 2010. Overall, the party's hopes hinge on a baseline of three races in Republican-leaning states, a couple of states President Barack Obama should carry by a significant margin and a few close contests in presidential swing states - where Romney's performance especially matters.
"It's one of those situations where there are enough close races in swing states that I think whoever wins the presidency will probably win the Senate," said Dan Judy, a Republican pollster at North Star Opinion Research.
That was not necessarily the case a month ago, when Missouri still appeared to be a likely pickup for the party and New Mexico remained a margin-of-error race. Since then, a plethora of polling showed Rep. Martin Heinrich (D) taking a solid lead over former Rep. Heather Wilson (R), and both national Senate committees pulled money out of that state. In Missouri, Rep. Todd Akin's remarks about "legitimate rape" potentially doomed the GOP's chances of defeating the most vulnerable Democratic incumbent of the cycle, Sen. Claire McCaskill.
With Missouri's status shifting and other developments, Democrats are more confident in their ability to hold on to the majority Nov. 6.
"It's far from in the bag, but it definitely looks better than it did about a month ago," said Mike Gehrke, a Democratic pollster at Benenson Strategy Group. "The races that were close then are close now, they just look better for us now."
Republicans must win four seats, net, to reclaim the majority. But the loss of any they currently hold would in turn increase the number of Democratic-held seats they must flip to assume control of the chamber. The most likely casualty at this point is the seat of retiring Sen. Olympia Snowe in Maine. Former Gov. Angus King (I) is favored and likely to caucus with Democrats if elected.