The change in Iowa means we now list five Democratic-held Senate seats as at least leaning to the Republicans: Arkansas, Montana, South Dakota, West Virginia, and the aforementioned Hawkeye State. In these states, the only Democratic incumbent running for reelection is Sen. Mark Pryor (D-AR), who according to poll averages is down about two to four points. At this point, we don’t see any hope for Democrats to win either Montana or West Virginia, so we’re moving both from Likely Republican to Safe Republican.

We’re doing that in part to differentiate those two states from South Dakota, which is more competitive but where former Gov. Mike Rounds (R) should survive in a three-way race that also features Rick Weiland (D), a former aide to Sen. Tom Daschle (D-SD), and former Sen. Larry Pressler, who served as a Republican but is now an independent. Weiland and Pressler are actually dividing about half of the vote, but neither seems likely to stop campaigning and endorse the other at this point — which, if it actually happened, could create a bipartisan coalition against Rounds.

If the Republicans follow through in those five races — which is far from certain, at least in Arkansas and Iowa — those potential gains could get them to 50 seats, so long as they hold all of their current ones. In light of Kansas, that is an assumption that is now much harder to make, because for the first time all cycle we’re now listing a Republican-held Senate seat as a Toss-up. Besides the Sunflower State, Georgia and Kentucky are other potentially problematic holds for the GOP.