An exterior view of the U.S. Capitol in Washington, DC, on September 9, 2024.
CNN — 

With just over a month until Election Day, the same competitive races continue to dominate the Senate landscape, but there are a few significant changes to the order of CNN’s ranking of the seats most likely to flip.

And in the final weeks, the degree to which these 10 races – which are mostly playing out in states Donald Trump either won or narrowly lost in 2020 – move in the same direction as the presidential contest will likely determine which party wins control of the Senate.

Republicans – who are virtually a lock to pick up the West Virginia seat and would need to either win the White House or pick up one more seat for the majority – have an incentive to nationalize many of their targeted races. Well-funded Democratic incumbents, for the most part, are touting statewide and local accomplishments and their support for abortion rights.

Two states that are part of the Democratic “blue wall” – and also key White House battlegrounds – move up on this month’s rankings, which are based on reporting, as well as fundraising, polling and advertising data. Pennsylvania and Wisconsin are now in the middle of the pack of flippable seats, along with Michigan, which remains at No. 4.

The oddity of this year’s fight for the Senate is that Democrats have consistently led in the public polling of key races, but it’s Republicans who are poised to gain seats and, potentially, control of the chamber.

That’s a reflection of the Senate map – but also increasingly some post-Labor Day tightening as GOP spending picks up and voters get to know their candidates. Still, no public general election polling that meets CNN standards has shown the Republican nominee ahead in any of the seats that Democrats are defending, save for West Virginia.

And two GOP targets – Arizona and Nevada – are moving down the list because Republicans have not kept the races as competitive as elsewhere. Earlier this year, those two states were Nos. 4 and 5. Now, they’re at 7 and 8.

At the same time, Democrats are trying to expand the map in hopes of mitigating potential losses. As CNN first reported last week, the Democratic Senatorial Campaign Committee is making multimillion-dollar TV investments in Texas and Florida. DSCC Chairman Gary Peters has insisted that this is extra spending that won’t take money away from their defensive priorities. Texas remains at No. 9 on CNN’s ranking, while Florida fell off the list earlier this year in favor of the race in deep-blue Maryland.

Nebraska is a new state generating political buzz, but it hasn’t earned a place on the ranking. Still, independent Dan Osborn’s challenge to GOP Sen. Deb Fischer has prompted the National Republican Senatorial Committee to start spending here, and elections analysts have moved the race out of the solid Republican category.

There remain lots of unknowns in Nebraska, but we’ll be watching to see how that race – and the 10 others – develop over the next month.