With a month to go before the midterm elections, the U.S. map keeps shifting in Democrats' favor. Senate seats in states that President Trump won comfortably are now seen as tossups and House seats that he carried by double digits are in danger of flipping.

At the same time, Democrats are struggling to coalesce around an ideological platform and face a steep financial disadvantage to Republicans. In some blue-leaning states, Senate GOP candidates are staging strong challenges, giving Republicans hope of potentially tempering any Democratic gains elsewhere-and forcing Democrats to devote money and energy to defending their home turf.

"While many have long predicted that Democrats will enjoy a 'blue wave' election, I think of it more as a 'red undertow,' which will pull many Republicans under and significantly trim the margins for many others," Charlie Cook, the founder of the nonpartisan Cook Political Report wrote recently. "A blue wave implies an endorsement or affirmation of Democrats and their policies. But Democrats' brand is still in tatters."

GOP held early Senate advantage

At the start of the year, the Senate map looked difficult for Democrats. Republicans have a 53-47 majority, while Democrats had few obvious pickup opportunities and were also playing defense in a number of states.

They had to defend Sen. Jon Ossoff in battleground Georgia and hold on to open seats in New Hampshire, Michigan and Minnesota. They saw the open North Carolina seat as a good target, and their best chance to take out a Republican was Sen. Susan Collins in Maine-but that was always going to be hard. Collins easily dispatched her Democratic opponent last time, and the Democratic leadership and grassroots were divided over the best candidate to take her on.

To get a majority, Democrats would have to make inroads in states that Trump had won, in most cases by wide margins. The Democratic Party was also struggling to excite its voters and donors, and there were signs that the party's left flank was gaining ground-potentially turning off independents.

A blue shift after U.S. strikes Iran

Trump launched the war with Iran at the end of February. Gas prices surged, and voters questioned whether he was breaking his pledge to keep the U.S. out of "forever wars" overseas. Trump also struggled to bring down high costs, and mortgage rates on homes hit new highs. His own polling has plummeted, including in states where a majority of voters had supported him.

Republicans also struggled with candidate recruitment and divisive primaries. In Texas, Trump supported scandal-plagued Attorney General Ken Paxton over sitting Sen. John Cornyn in what became a nasty primary fight. Paxton ultimately won, making the race more competitive for the Democratic candidate.

All those developments put more red states in play. Democrats also grew increasingly confident about keeping Georgia in their column and picking up North Carolina, where former Gov. Roy Cooper looked strong. Alaska, Texas and Iowa were solidly on the radar as potential flips. Even some deep red states started to appear competitive, such as Kansas. Still, past polling showing Democratic strength in red states has proved illusory, tempering expectations.

"The map gets better every day," Democratic strategist Caitlin Legacki said. But given polling misses in primaries and recent cycles, "I think it's really, really dangerous for Democrats to start counting our chickens."

Map grows but Democrats struggle to close the deal on home turf

At the same time, Democrats have had candidate issues of their own. Graham Platner, a progressive-leaning oyster farmer, bucked the party establishment to become the Democratic nominee in Maine until an allegation of sexual assault forced him out of the race. Maine voted for former Vice President Kamala Harris in 2024, but GOP Sen. Susan Collins remains formidable. She is facing Democrats' new candidate, former state Senate President Troy Jackson, in what is rated a tossup.

In Michigan, a far-left candidate beat out the establishment choice to become the Democratic nominee. But the candidacy of Abdul El-Sayed, a former public health official, has divided the Democratic Party, and analysts say Republicans have a shot at winning the seat. New Hampshire Democratic Rep. Chris Pappas was seen as the Democratic establishment's choice, but he is locked in a tight race against Republican former Sen. John Sununu.

Analysts still give Democrats a slight edge in both Michigan and New Hampshire.

The current snapshot

Democrats' inroads in red areas and Republicans' continued hope in blue ones have left the Senate up for grabs.

If Democrats gain control of the Senate, they would have significant power to block or reshape Trump's agenda, control the chamber's committees and influence judicial and executive-branch appointments. They also could use their investigative and oversight powers to scrutinize the administration's conduct.

The House has long looked like a more likely pickup for Democrats, even as the GOP is expected to make gains from redistricting. Democrats only need a handful of seats to flip the majority, and historically the party that controls the White House-in this case, Republicans-almost always loses members in the midterm elections.

That House map has continued to expand entering the fall, with Democrats now playing in districts that Trump won by double digits just two years ago. The Cook Political Report projects Democrats will flip a net of five to 15 seats, giving them 220 to 230 in the next Congress.

Working against Democrats is their financial gap with Republicans, with GOP committees and super PACs far outraising their Democratic counterparts. GOP groups, including the Trump-aligned MAGA Inc., have unleashed their cash this fall, pouring money into tight House and Senate races in the hopes of turning the tide in their favor.

Money can change the race, "but it doesn't always," said Doug Heye, a former communications director for the Republican National Committee. "You're trying to fortify a levy to prevent water from coming over, and it's a hard thing to do," Heye said.