BELLEVILLE, Ill. >> Sen. Mark Kirk says he’s ready for “Hurricane Trump.”

The Illinois freshman was the first congressional Republican to withdraw his support for Donald Trump after the presidential candidate disparaged the impartiality of an East Chicago-born judge of Mexican heritage. Kirk was among the first to urge Trump to quit the race earlier this month after a leaked 2005 video revealed Trump bragging about grabbing women by their genitals.

“Among all the guys in tough races, I’m probably the best-prepared to weather the Trump storm,” Kirk told McClatchy in an interview aboard his campaign bus in Chicago.

But if he’s the best-prepared Republican incumbent, the Republicans could be in real trouble.

Three weeks before the elections, Kirk trails Rep. Tammy Duckworth, D-Ill., who graduated from McKinley High School in Honolulu and attended the University of Hawaii.

Kirk is considered the most vulnerable among a half-dozen Republican incumbents whose races will determine whether the party loses control of the Senate.

They lose power if they lose four seats and Hillary Clinton is president; five, if Trump wins.

And they are vulnerable in at least six states: Illinois, Missouri, New Hampshire, North Carolina, Pennsylvania and Wisconsin.

Kirk faced odds even before Trump became the Republican nominee: Kirk is a Republican running in a state that hasn’t voted for a Republican presidential candidate since 1988.

“It would take an extreme number of crossover voters or an extreme depression of Democratic voters” for Kirk to win, said Nathan Gonzales, the editor of the Rothenberg & Gonzales Political Report, a nonpartisan newsletter that rates the Illinois contest as leaning Democratic.

Duckworth, a two-term member of the House of Representatives, leads Kirk by 7 percentage points in a Real Clear Politics polling average. Kirk insists that the race is closer.

To gain ground, Kirk is walking a moderate line, stressing a message of fiscal conservatism to appeal to the right while touting his support for same-sex marriage, abortion rights and gun control, to woo Democrats and center-left independents.

But his middle-ground approach and distancing himself from Trump are grating on some of the state’s staunch conservatives and tea party supporters, constituencies he’ll also need if he’s to overtake Duckworth in the closing weeks.

“Yes, we’re concerned about the Senate, but a lot of Republicans aren’t fond of Mark Kirk,” said Denise Cattoni, a DuPage County resident who’s founder of the Illinois Tea Party. “Donald Trump said something to make Mark Kirk squeamish, so he won’t vote for Trump. He just wants to stay in Washington.”

Try as Kirk might to separate himself from Trump, the top of the ticket casts a long shadow over the senator’s race and other down-ballot contests.

In dozens of interviews between Belleville and Chicago, several voters expressed frustration with having to choose between Trump, whose temperament and alleged treatment of women they abhor, and Clinton, whom they consider untrustworthy.

That frustration is seeping into down-ballot races.

Judy Klohr, a 71-year-old from Lebanon, Ill., comes from a military family that’s been reliably Republican. She plans to vote a straight Democratic line next month because of Trump, even though Kirk has disavowed his party’s standard bearer.

“He is, to me, Hitler reincarnated,” Klohr said of Trump. “He scares me a lot.”

Connie Morriss, a 61-year-old retired naval intelligence specialist from Belleville, said Kirk and everyone else in Congress had done little to help Americans and they all needed to be replaced.

“I’m not voting for any incumbents; they’ve been in there too long,” Morriss said as she sold wares at the Swansea Farmers Market last week. “Kirk’s been in for six years. What has he done?”

A few booths away, Sue Sippel lamented how the ugliness and negative campaigning at the top of the Republican and Democratic tickets are leading her to skip voting altogether.

“There’s nothing there that interests me, from president to senator on down,” the 65-year-old Belleville resident said while helping to her sell handmade jewelry. “I’ve always voted. I just don’t know what I’m going to do this year.”

Over at Max and Benny’s deli in the Chicago suburb of Northbrook, Gary Anders is the type of ticket-splitting voter Kirk desperately needs.

“I believe if you have a Democratic president it behooves you to have a Republican Congress,” said Anders, a Republican from Island Park, Ill.

Though not as heated as the Trump-Clinton matchup, the Illinois U.S. Senate battle has been contentious.

Duckworth has attacked Kirk for making controversial comments, including referring to President Barack Obama as “drug dealer in chief” after the U.S. paid Iran $400 million linked to the release of American prisoners there and for jokingly referring to bachelor Sen. Lindsey Graham, R-S.C., as a “bro with no ho.” In an editorial debate earlier this month, Kirk conceded that he has “been too quick to turn a phrase.”

Kirk has lashed out at Duckworth for voting for the Iran nuclear deal in the House of Representatives and has pressed her about a government lawsuit filed against her during her tenure as the head of the state’s Department of Veterans Affairs.

The Illinois Senate race has been historic, with two candidates who have physical disabilities and often use wheelchairs campaigning against each other for the first time.

Duckworth, an Iraq War veteran, lost her legs and partial use of her right arm when the Black Hawk helicopter she was flying was shot down in 2004. Kirk suffered a massive stroke in 2012 that left him partially paralyzed on his left side and affected his speech.

His health has become a campaign issue since the Chicago Tribune editorial board endorsed Duckworth last week, saying Kirk is no longer up to rigors of the job.

“While a stroke by no means disqualifies anyone from public office, we cannot tiptoe around the issues of Kirk’s recovery and readiness,” wrote the Tribune. “Our reluctant judgment is that, due to forces beyond his control, Kirk can no longer perform to the fullest the job of a U.S. senator.”

Kirk called the editorial a “cheap shot,” particularly since he’d released a letter last month from his treating physician, who said the senator had made a “full cognitive recovery” from the stroke.

“I’ve been sucker-punched in the past and I’ve always got up and prevailed,” Kirk said. “Last I checked, they hadn’t gone to medical school.”