Democratic chances of retaking the Senate — 62 percent in polls-only and 64 percent in polls-plus — haven’t moved much since mid-October, bouncing between about 60 percent and 75 percent. But while the overall topline hasn’t changed much, a number of competitive races have.

Across the eight closest races, four have seen major shifts over the past few weeks. One of those (Pennsylvania) has shifted towards the Democratic candidate, while the other three (Indiana, New Hampshire and Wisconsin) have lurched towards the Republicans.

DEMOCRATIC MARGIN CHANCE OF WINNING STATE OCT. 20 NOV. 3 CHANGE OCT. 20 NOV. 3 CHANGE Indiana +3.6 +0.8 -2.8 70.2% 55.4% -14.8 Wisconsin +8.2 +5.7 -2.5 93.6 90.3 -3.3 New Hampshire +2.5 +0.8 -1.7 67.1 56.0 -11.1 North Carolina -0.8 -1.5 -0.7 43.1 34.3 -8.8 Missouri +1.3 +0.6 -0.7 58.9 55.2 -3.7 Florida -3.9 -4.3 -0.4 25.7 17.4 -8.3 Nevada +1.1 +1.2 +0.1 57.1 59.5 +2.4 Pennsylvania +0.7 +2.9 +2.2 55.4 73.5 +18.1 How key Senate races have shifted over the last two weeks Based on FiveThirtyEight’s polls-plus forecast as of 10 a.m. on Nov. 3

Pennsylvania

The most dramatic shift has been in Pennsylvania. Polls long showed a tossup between incumbent Republican Pat Toomey and Democratic challenger Katie McGinty, but the race is clearly tilting in McGinty’s direction now. Our polls-plus forecast gives her a 74 percent chance of winning, and McGinty hasn’t trailed in a poll in over two weeks and has opened up her largest lead in the FiveThirtyEight polls-plus forecast for the entire year.

Voters in Pennsylvania appear to be treating the presidential and Senate races as one, as Hillary Clinton and McGinty have about equal chances of winning the Keystone State. That’s bad news for Toomey, who was always an odd fit in Pennsylvania: He’s very conservative; the state leans blue. Toomey was elected in a midterm year; such elections have had more Republican-friendly electorates of late, and that was true in 2010, when Toomey won amidst a national GOP wave nationally. He was always going to have more trouble in a presidential election cycle.

Toomey has also tried to have it both ways when it comes to Donald Trump. He hasn’t endorsed Trump, but he hasn’t ruled out voting for him, either. That position doesn’t appear to be providing enough distance from Trump for Pennsylvania voters.

Indiana

Something similar — though with the parties reversed — has been happening in Indiana. Democrats were able to recruit former Sen. Evan Bayh to run in the state’s open race, and it looked as if he was going to win this seat back comfortably. Indiana, though, is a fairly red state that Trump is likely to carry easily, and it seems to be returning to form in the Senate race, too. Bayh has seen his numbers drop throughout the summer and fall. Republicans have attacked Bayh for his ties to lobbyists as well as the amount of time he has spent out of state. At the same time, Republican Todd Young has improved his name recognition. Still, Young is slightly behind Bayh with a week to go. We’ll have to wait and to if Young’s climb carries through until Election Day. Bayh is still just the slightest of favorites in our polls-plus forecast, with a 55 percent chance of winning.

Wisconsin

Perhaps the most intriguing contest of this group is Wisconsin. Republican Sen. Ron Johnson had been left for dead. With a brief exception at the beginning of October, the polls all year had good news for former Democratic Sen. Russ Feingold. Then a funny thing happened: Democratic and Republican organizations started investing a ton of money into the state in a way they hadn’t for Illinois (another state that seemed close to a certain Democratic pickup). The question was why? Well, they clearly knew what they were doing. A new poll by the Marquette Law School, the best pollster in the state, found Feingold up only 1 percentage point. SurveyMonkey, too, indicates that Johnson has made up ground. The FiveThirtyEight models, though, are still skeptical that the race in Wisconsin is really as close as Marquette puts it. Our polls-plus model has Feingold as a 90-percent favorite. But if Marquette is right on the nose, Republican chances of holding the Senate are better than our model suggests.

New Hampshire

The race between Democrat Maggie Hassan and Republican Sen. Kelly Ayotte looks as if it will go down to the wire. Although Hassan had gained a small lead in the polls a few weeks ago, the race has generally been tight all year. New Hampshire is an elastic state (i.e., many swing voters) so Ayotte’s ability to close the gap makes sense. Keep in mind, Trump has been gaining in the polls in the Granite State, which may be causing a downballot effect. New Hampshire may end up, like Pennsylvania, with the party who wins the presidential race also winning the Senate race.

Overall, Democrats need a net gain of four seats to take control of the chamber. They are leading in enough states to do so at this point, but they have little margin for error. There are more close Senate races this year than at any point in the past 30 years. There is no sign of a wave building on either side, and it looks like it’ll remain that way until Election Day.