An up-and-coming Illinois Republican who rode into Congress on the 2010 GOP wave is struggling to navigate the political conditions created by the rise of Donald Trump.

Trump's success has caused headaches for down-ticket Republicans nationwide, and Rep. Adam Kinzinger, R-Ill., has found himself in the middle of party factions that want to embrace or reject Trump. The thought of Democrats taking back the House may have appeared unthinkable one year ago, but Trump's nomination may expose blue state conservatives and swing state moderates if his poll numbers continue to plummet.

After defeating an incumbent Democrat in 2010, Kinzinger was forced to oust an incumbent Republican two years later because of redistricting. Kinzinger won the redrawn district on the coattails of 2012 GOP nominee Mitt Romney, who won portions of the district where President Obama triumphed in 2008.

Kinzinger easily dispatched an insurgent Tea Party challenger and won re-election in 2014, amid a Republican takeover of the governor's mansion in the Land of Lincoln. Kinzinger once again won his primary earlier this year, as Trump ran away with Illinois' presidential primary. But Trump's top opponent, Texas Sen. Ted Cruz, triumphed in counties that make up portions of Kinzinger's district during the 2016 primary.

With fewer than 100 days to the November election, the congressman voiced his opposition to Trump on national television. He slammed Trump on CNN last week and added, "I just don't see how I get to Donald Trump anymore."

Seven days later, Kinzinger made clear he is not actively opposing Trump in an email to fellow Republicans.

"I am deeply aware that many of you, who have generously and faithfully supported me over many years are also generous and faithful supporters of Donald Trump. I fully respect and appreciate that and do not in any way wish to discourage you from your fervent support," Kinzinger wrote. "There are many compelling arguments on why it is necessary for the Republicans to win the White House and we certainly don't need another President Clinton."

Kinzinger's rejection of anti-Trump Republicans inadvertently reveals the challenges he's facing en route to re-election. Admonishing his party's nominee damages his standing with Trump supporters and could prove calamitous for Kinzinger.

In his email, Kinzinger wrote about his "fear" that Trump would undermine conservatism, but he said he remains hopeful that Trump would become a changed man.

"I have not ruled out ever supporting him, in fact my hope is that the last 72 hours is indicative of the new Donald Trump ... my fingers are crossed," Kinzinger wrote in the email distributed on Wednesday morning.

Kinzinger's email was sent fewer than 24 hours after Trump wondered aloud whether "Second Amendment people" might be able to thwart judges picked by Hillary Clinton if she became president.

Maura Gillespie, a Kinzinger spokeswoman, told the Washington Examiner the email was meant to be distributed on Monday — before Trump's remark — but the congressman's offices "were closed for staff training meetings out in Illinois on Monday and Tuesday."

Kinzinger's spokeswoman did not answer questions about whether Trump's controversial comments about Clinton that may have piqued the interest of the Secret Service had caused the congressman and Air Force veteran to change his mind since writing the email.

But Kinzinger's letter to his fellow Republicans appeared to end his week-long flirtation with embracing the anti-Trump members of his own party. Kinzinger's email showed a markedly different tone from the interview on CNN where he struggled to come up with any compelling argument as to how he could vote for Trump.

"Donald Trump for me is beginning to cross a lot of red lines of the unforgivable in politics and so I'm not going to support Hillary, but in America, we have the right to write somebody in or skip the vote," Kinzinger said on CNN. "I just don't see how I get to Donald Trump anymore."

Kinzinger first endorsed former Florida Gov. Jeb Bush for president, then joined Florida Sen. Marco Rubio's cause when Bush quit. With both men having lost the GOP primary, he told CNN he hoped to "mildly endorse" Trump by the Thursday of the GOP convention in July. He decided against it after seeing Trump's comments about NATO and Trump's "unbelievable spat" with the family of deceased veteran Capt. Humayun Khan.

Kinzinger's latest comments in the Wednesday email do not indicate that he would definitely vote for Trump, but reveal a noteworthy shift in his thinking.

The Illinois Republican did not tell CNN last week which alternative to Trump and Clinton he would consider supporting but said, "There's a bunch of people on the ballot; there's a write-in option." The congressman's letter to fellow Republicans one week later suggested he's headed in a much different direction.

"I have attempted since the beginning of my time in politics to avoid being the kind of person who tip toes around my true thoughts," Kinzinger wrote in the email to Republicans. "I believe in boldness (one of Trump's attractive qualities) and that I have a responsibility to defend the mission of this God Blessed nation."

It's a fine line many Republicans whose primary electorates voted for Trump but whose districts are vulnerable to Democratic takeover may have to walk until November.