Sunday morning, the GOP's chances of taking the Senate rose to their highest yet in Vox's average of the major forecasting models. The new release of the highly-respected Des Moines Register poll was particularly brutal for Democrats, since it gave Republican Joni Ernst a sizable seven point lead on Democrat Bruce Braley.
But the big-picture news for Democrats is even worse. According to several of the models, it now actually looks likelier that the GOP will end up with a net gain of 8 or more Senate seats — putting them at 53 or more seats in total — than that the Democrats will manage to hold on to the chamber.
Republicans lead in polls in the contests for 8 Democratic-held seats: West Virginia, Montana, South Dakota, Arkansas, Louisiana, Alaska, Iowa, and Colorado. If they win those, one of three things has to happen for the party to hold on to that 8 seat gain. Either (1) the GOP holds on to both of the seats it's defending that still look competitive — Kansas and Georgia, (2) a Republican wins an additional victory in North Carolina or New Hampshire, or (3) independent Greg Orman wins in Kansas and decides to caucus with the Republicans because they already have a clear majority, as he's promised.
In the estimates of several models, it now looks likelier that one of those three scenarios will occur, than that Democrats manage to defy polls and win victories in enough key states to keep their majority. 'Democrats are becoming increasingly dependent on the possibility that the polls will prove to be "skewed,"' Nate Silver wrote Saturday night.
Keeping the Senate was always going to be a challenge for Democrats this year, since they were defending so many seats in deep red states. But losses in Iowa and Colorado, swing states that Obama twice won, will be tougher to explain away if they transpire. And though Democrats will face a much more favorable map of Senate seats up in 2016, a larger GOP win this year would make it more difficult for the Democrats to regain control next cycle.