Missouri Secretary of State Jason Kander, a Democratic candidate for Senate, tours a facility in Chesterfield, Mo. Democratic hopes for retaking the Senate increasingly rely on candidates like Kander, who are running in states that President Obama lost in 2012. (Sid Hastings/Associated Press)

Democrats are now facing a tougher road to capturing the Senate majority as the presidential race tightens and Donald Trump is not proving to be the dramatic drag on down-ballot candidates that Republicans once feared.

Trump’s resilience and faltering Democratic campaigns in battleground states mean the fight for the Senate has settled into a knuckle-to-knuckle brawl likely to result in a chamber that will be closely divided or potentially even tied.

Democrats can still manage to win the four or five seats they need to claim the Senate majority, but the battle has shifted from purple states that Barack Obama twice carried — Ohio and Florida — to Indiana, Missouri and North Carolina, where Obama lost in 2012.

While Democrats are continuing their efforts in select states to tie incumbent Republican senators to Trump, Republicans are looking to flip that script in those redder states, yoking Democratic candidates to their own unpopular nominee.

“Evan Bayh voted with Hillary Clinton up to 85 percent of the time,” a voice-over intones in an ad now being aired in the Hoosier State by a major Republican super PAC. “Bayh voted with them; not with Indiana.”

The significant shift in the Senate battlefield appears to be the result of voters separating Trump — once considered so toxic that House Speaker Paul D. Ryan (R-Wis.) waffled about whether to support him — from Republicans running on the same ballot with him. That recognition could lead to more voters splitting their ticket between Clinton and a Republican House or Senate candidate.

“There is very much a feeling among voters that Donald Trump is sort of his own brand,” said Ian Prior, the communications director of the GOP-allied Senate Leadership Fund super PAC, citing internal research. “People don’t view him as this traditional Republican where he says something and that means that everybody else in the House or Senate must agree with him.”

Trump is also holding his own at the top of the ticket, with a new Washington Post/ABC poll showing him locked in a virtual tie with Clinton among likely voters, with Clinton leading 46 to 44 percent.

With six weeks until Election Day, a new map has emerged as Democrats trying to buck recent history in winning back the majority in a presidential election year. Over the past 60 years, the majority has only changed hands once in those 15 presidential elections — in 1980, when Ronald Reagan’s landslide swept Republicans into the Senate majority.

As recently as June, Democrats saw Ohio and Florida as key battlegrounds, booking a combined eight figures worth of television time there. Those states are no longer seen as prime pickup opportunities.

In Ohio, former governor Ted Strickland has been badly outraised and outspent by incumbent Sen. Rob Portman, and national Democratic groups have withdrawn ad reservations as he has lagged in the polls.

In Florida, Rep. Patrick Murphy is in striking distance of incumbent Sen. Marco Rubio, but the Democrat had been forced to fend off questions about his resume in a big state where television time is pricey.

Democrats’ hopes of expanding the Senate map into solidly Republican states such as Arizona, Georgia and Arkansas have not panned out. But they appear to be on track to pick up GOP-held seats in Illinois and Wisconsin, and they are in very competitive races in Pennsylvania and New Hampshire, as well as Nevada, where they are hoping to keep control of the seat of retiring Sen. Harry M. Reid (D).

Democrats need to flip five seats to win an outright majority — four if Clinton wins, allowing her running mate, Tim Kaine (Va.), to cast tiebreaking votes.

Sen. Jon Tester (Mont.), chairman of the Democratic Senatorial Campaign Committee, played down the need for Democratic candidates to break with Clinton.

“What they need to show is what they’re going to do when they get back here and show the fact that the Republicans really haven’t done anything,” Tester said in a Capitol Hill interview. “If they tailor that to each one of their states, they can be effective. And they have been, by the way.”

That makes the trio of Indiana, Missouri and North Carolina suddenly crucial. And while Democratic candidate are locked in tight races there, according to recent polls, Republicans have started shifting resources into those states, and they believe they have a potent message to push.

The Senate Leadership Fund, which ran the Indiana spot and has booked nearly $60 million worth of ads around the country, recently debuted ads targeting Jason Kander, the Missouri secretary of state running to unseat Sen. Roy Blunt (R-Mo.), as a “career politician” who is “too liberal for Missouri.”

Back in March, after Kander appeared at an event with Clinton ahead of the state’s Democratic primary, Blunt issued a web video of his remarks touting Clinton as the “most prepared” person since George Washington to run for president.

More recently, Blunt’s campaign went on air with an ad asking this question: “Do you believe we’re headed in the right direction? Hillary Clinton and Jason Kander do.”

Prior of the Senate Leadership Fund said Democratic candidates are “attached at the hip” to Clinton due not only to their refusal to break with her, but also the Clinton family’s long history in the party.

Some Democrats are privately concerned that voters in a few states, a small sliver but potentially decisive, are making a conscious decision to support Clinton but vote against the Democratic Senate candidate as a way to put a check on her power in office. That would echo the argument that some Republicans Senate candidates like John McCain (Ariz.) are making not to give Clinton a “blank check” as president.

In New Hampshire, for example, Gov. Maggie Hassan (D) is dramatically more popular than Clinton in that state, but she is struggling in her race against Sen. Kelly Ayotte (R).

A late August poll by the University of New Hampshire found Hassan maintaining her popularity, with 52 percent of voters having a favorable impression of her while just 37 percent held an unfavorable view, while Ayotte was viewed favorably by 46 percent and unfavorably by 42 percent of voters. Yet that poll showed the race in a statistical tie, 44 percent for Hassan to 42 percent for Ayotte, and two other recent polls have given Ayotte the lead.

Most New Hampshire polls give Clinton a lead over Trump, despite her own brutal favorable ratings. An early September poll there by Emerson College found that 60 percent of New Hampshire voters have an unfavorable impression.

In Indiana, Bayh is drawing on decades of goodwill earned during the three Senate terms served by his father, Birch Bayh, as well as his own tenure as governor and senator. But his GOP opponent, Rep. Todd C. Young, is getting major help from outside groups in his bid to convince voters that Bayh has lost touch with the state.

In North Carolina, former state lawmaker Deborah Ross has taken advantage of a lackluster campaign from incumbent Sen. Richard Burr (R) as big-time ad money is starting to flow in the Tar Heel State.

And in Missouri, Kander has waged an energetic bid that has played up his own military background as well as Blunt’s long tenure in Washington. A striking new ad shows Kander assembling an assault rifle blindfolded, while he discusses his Army service and his support for gun buyer background checks.

Kander has tried to run as an independent Democrat, distancing himself from Obama and Clinton — criticizing the Iran nuclear deal, for instance, and recent Obama administration environmental regulations. He recently brought Vice President Biden in to campaign for him and in an interview afterward said he has “no plans” to bring Obama to his state.

“Not everybody who goes to Washington becomes Washington,” Kander said in an interview last month, explaining why Biden would be welcomed there.

Sen. Roger Wicker (Miss.), chairman of the National Republican Senatorial Committee, said he was “not surprised about anything” — including Kander’s competitive race against Blunt.

“We’ve always viewed Jason Kander as very glib and very photogenic, and we knew he hired a great ad agency,” Wicker said.

But Blunt and his fellow incumbents “are just very talented legislators,” Wicker added. “They’re in step with their states, and they’ve been working hard. That’s how you win an election in a competitive state.”

Paul Kane contributed to this report.