Illinois Democrats have serious searching to do to find a formidable candidate to run against GOP Gov. Bruce Rauner in 2018.

Sen. Dick Durbin, D-Ill., re-elected to a top Senate leadership spot on Wednesday, and the Democrats best bet to mount a powerful challenge to Rauner, said he is staying in the Senate.

With Durbin removing himself from the gubernatorial contest, Rep. Robin Kelly, D-Ill., told the Chicago Sun-Times she is considering a bid.

Durbin was the clear favorite of Illinois Democrats at the Democratic National Convention in Philadelphia last summer.

Durbin said in Philadelphia that he wanted to wait until after the presidential and Senate leadership elections before deciding if he wanted to remain in the Senate.

OPINION

The shocking win of President-elect Donald Trump last week firmed up Durbin’s resolve to stay in the Senate. Durbin’s thinking is, I am told, that Trump’s election makes it important for Senate Democrats to keep a check on his power — and that’s a job Durbin wants to do.

Durbin, the “whip” since 2005, said in a statement, “I am honored that the Senate Democratic Caucus has again unanimously supported my service as Whip.

“The responsibilities of our caucus grew last Tuesday, and my experience in this role and strong relationships with my colleagues will help me continue to be an integral part of this leadership team.”

Kelly told the Chicago Sun-Times, “People have come to me about giving thought to running for governor, being encouraging, asking is this something I would consider.

“I love my seat. I love being here,” Kelly said, a reference to Congress. “But I would say, I’m honored to be asked, but at this point, I would not rule anything out.”

Kelly won her third election last week for the far south suburban 2nd Congressional District seat. In 2013, she replaced the disgraced former Rep. Jesse Jackson Jr., and since coming to Congress she has made curbing gun violence her central issue.

Kelly was the 2010 Democratic nominee for state treasurer, a former member of the Illinois House and a former chief of staff to former Illinois State Treasurer Alexi Giannoulias.

A Matteson resident, Kelly has downstate Illinois ties from her 2010 campaign and her years of living in Peoria, where she attended Bradley University, picking up undergraduate and grad degrees.

Kelly had considered running for Senate but decided against it when it became clear Rep. Tammy Duckworth, who defeated Sen. Mark Kirk, R-Ill., last week, had the inside track for the Democratic nomination.

The Illinois 2018 governor’s contest is different. With Durbin out, there is no anointed insider or consensus candidate.

Attorney General Lisa Madigan is locked out as long as her father, Illinois House Speaker Michael Madigan — who doubles as the state Democratic party chairman — remains in office.

There is some thought that the Illinois Democrats have to find a mega-millionaire who can self-fund a campaign in order to compete with the tens of millions of dollars the jumbo rich Rauner can pour in his quest for a second term.

That puts Democratic activist J.B. Pritzker in play. Pritzker was one of Clinton’s biggest donors and fundraiser and knows the political ropes.

Chris Kennedy, from the famous political family, stuck a toe in the gubernatorial water at the Democratic convention but hasn’t done much since.

There could be other models for Illinois Democrats to consider.

Vermont Sen. Bernie Sanders almost beat Clinton in Illinois in the March Democratic primary. We know from the stolen, leaked WikiLeaks memos just how worried Clinton’s team was about Sanders catching Clinton in her home state.

Sanders built a strong Illinois presidential campaign with activists who backed Cook County Board Commissioner Jesus “Chuy” Garcia’s mayoral run against Rahm Emanuel.

Clinton’s backers are demoralized, as are almost all Democrats, still absorbing the impact of a Trump White House coming after President Barack Obama’s two terms.

Sanders is still on a roll. He is determined to keep up “our revolution” — and that’s also the name of his just published campaign book. In Illinois, the Sanders faction is the most organized, agile and possibly motivated bloc.

They are, if they keep up Sanders’ “revolution,” a potential populist force against Rauner if they find the right candidate to get behind.