The Senate map has expanded in Democrats’ favor heading into the fall, and that’s bad news for Republican incumbents.

Eight Republicans now rank among the most vulnerable senators as the GOP defends its majority in the Senate, with Georgia’s David Perdue once again making the list. Georgia has become an increasingly competitive Senate and presidential battleground, putting pressure on both of its Republican senators who are on the ballot this cycle.

Perdue’s entry pushes Michigan Democratic Sen. Gary Peters off the list. While Peters still has a real race against Republican John James, the state appears to be a less competitive presidential battleground for President Donald Trump’s campaign. Michigan went by a slim margin for Trump in 2016, but former Vice President Joe Biden has the edge in recent polling. While James has outraised Peters the last four quarters, the Democrat had a cash-on-hand advantage of nearly $11.6 million to James’ $9.2 million as of July 15.  

The first half of the list has not changed since the start of the cycle, with Alabama Democrat Doug Jones once again taking the No. 1 spot. The 2016 presidential results in these states were factored into the rankings, along with conversations with strategists on both sides of the aisle and race ratings from Inside Elections with Nathan L. Gonzales.

[See October updates to lists of most vulnerable House members and senators]

After a prolonged GOP primary, Republicans finally have their challenger to take on Jones: former Auburn University football coach Tommy Tuberville, who had Trump’s backing in his primary against former Attorney General Jeff Sessions. Jones maintained a sizable financial advantage in the race as of June 30, with $8.8 million on hand to Tuberville’s $562,000. But the Democrat still faces an uphill battle given Alabama’s partisan lean. Jones won a low-turnout special election in 2017 against a deeply flawed GOP candidate, former Alabama Supreme Court Chief Justice Roy Moore. This year he’ll need thousands of Trump voters to split their tickets, a tall order in the ruby-red Yellowhammer State. 

Former Democratic Gov. John Hickenlooper won the Democratic nod in June to take on Gardner, who is one of two GOP senators running in states that backed Hillary Clinton for president in 2016. Republicans believe they can effectively attack Hickenlooper over a finding by Colorado’s Independent Ethics Commission that he violated the state’s ban on gifts for public officials while in office. (Hickenlooper’s campaign has called the allegations “political smears.”) But GOP attacks may not be enough to help Gardner overcome the Centennial State’s leftward shift in recent years. Gardner did have a cash-on-hand edge at June 30, with $10.7 million to Hickenlooper’s $4.6 million.

[Here’s the 10 most vulnerable House members]

The general election between McSally and Democrat Mark Kelly, a retired astronaut and Navy veteran, has been underway for months with Kelly unopposed in Tuesday’s Senate primary. Kelly built a national profile combating gun violence with his wife, former Rep. Gabrielle Giffords, and has continued his prolific fundraising. His July 15 report showed him with $21.2 million on hand to McSally’s $11 million. Arizona is also expected to be a presidential battleground, and some public polling shows McSally faring worse than Trump.

The National Republican Senatorial Committee, along with conservative outside groups such as Americans for Prosperity Action, have invested heavily on Tillis’ behalf in recent weeks, but it may not be enough to compensate for Trump’s eroding support in the Tar Heel State. The NRSC disclosed spending shy of $4 million in ads against Tillis’ challenger, Democrat Cal Cunningham, an Army veteran and former state senator. Democratic super PACs are also making the race a priority. Tillis had a slight cash advantage of nearly $6.9 million to Cunningham’s $6.6 million as of June 30, but like other Democratic challengers, Cunningham has outraised the incumbent recently. 

Collins has touted her COVID-19 response work in the Senate, including on the Paycheck Protection Program, but if recent polls are any indication, it hasn’t significantly bolstered her odds of winning reelection in a state that rejected Trump four years ago. Collins’ 2018 vote to confirm Brett M. Kavanaugh to the Supreme Court became a rallying cry for her opponents and created a literal windfall of more than $3.5 million for her Democratic challenger, Sara Gideon, the state House speaker. Before that transfer of cash, Collins had a slight advantage with $5.6 million to Gideon’s $5.4 million as of June 30. Outside groups, which are already spending in the race, will continue to fork over millions as Election Day approaches.  

As an appointee who now has to run to stay in office, Loeffler’s personal fortune was expected to mean she would not need support from national Republicans or outside groups. But she has been in a bitter feud with Republican Rep. Doug Collins in the November special election in which all candidates run on the same ballot, and some outside groups have had to step in to support her. Even after the Justice Department closed the investigation with no charges filed, Loeffler may have lingering damage from insider trading allegations over coronavirus-related stock sales. And as the co-owner of the Atlanta Dream basketball team, Loeffler’s criticism of the WNBA for its support of the Black Lives Matter movement could turn off college-educated suburban voters. Democrats have a fragmented field, though they appear to be consolidating around Atlanta pastor Raphael Warnock. 

Real estate executive Theresa Greenfield, with the Democratic Senatorial Campaign Committee’s backing, won the June primary to take on Ernst, who’s seeking a second term. The race has looked increasingly competitive as Trump has struggled in the Hawkeye State and across the country. Republicans have launched attacks against Greenfield’s business record, while Democrats have sought to cast Ernst as a partisan who’s out of touch. Like other Democratic challengers, Greenfield leveraged her digital operation and outraised Ernst in the most recent fundraising quarter. But Ernst had a cash-on-hand advantage with $9.1 million  to Greenfield’s $5.7 million. 

Democratic Gov. Steve Bullock entered the race against Daines five months ago, and he already had more in his campaign account than Daines — $7.6 million to the incumbent’s $7.1 million — as of June 30. Bullock remains popular and visible as he leads the Treasure State’s response to the coronavirus pandemic, though the increase in cases statewide, along with economic tumult, could factor into voters’ consideration come November. Outside groups, such as the Democratic-aligned Senate Majority PAC, have made the race a priority. Though Montanans voted big for Trump in 2016, the president is not likely to match that margin this year, and as with other vulnerable GOP senators, he may be a drag on Daines. 

Markey has narrowed the polling gap with Rep. Joseph P. Kennedy III ahead of the Sept. 1 Democratic primary. But he’s still in serious trouble. Markey has won endorsements from the stars of the party’s progressive wing, such as New York Rep. Alexandria Ocasio-Cortez, who cut a late-July ad for him. The 73-year-old incumbent served 18 terms in the House before moving up to the Senate seven years ago. Kennedy, who turns 40 in October, is in his fourth House term. Few policy differences separate Markey from Kennedy, scion of a political dynasty with deep Massachusetts roots. Markey ended June with a cash-on-hand edge over his challenger, $4.8 million to $4.2 million, but a pro-Kennedy super PAC is preparing to launch ads.

Georgia’s changing political landscape and emergence as a pivotal presidential battleground has outside groups funnelling millions into both the state’s Senate races. That’s a cause of concern for Perdue, whose challenger Jon Ossoff established himself in a 2017 special election as a prolific fundraiser. The Democrat, a former congressional aide who heads a documentary film production company, has not yet come close to matching the $27 million he raised in losing the most expensive House contest ever. Ossoff outraised Perdue in the two most recent quarters, but he had $2.5 million on June 30 to Perdue’s $10.7 million. Still, Ossoff proved his mettle by carrying enough of the vote in his heated primary to avoid a runoff. Perdue, a former businessman, has pitched himself as a political outsider and is campaigning on his proposal for education funding to help schools reopen. Ossoff has focused on corruption and has hammered Perdue for his business interests.