SPRINGFIELD, Ill. (AP) — Illinois Republicans rallied around first-term U.S. Sen. Mark Kirk on Wednesday after a top fundraiser briefly suggested that the moderate elected to Barack Obama's former seat should abandon his re-election bid due to a recent series of public gaffes.

Kirk, who suffered a debilitating stroke in 2012 but is eyeing a second term next year in one of the nation's most competitive Senate races, was widely criticized last month after being heard on an open microphone calling South Carolina Sen. Lindsey Graham a "bro with no ho" because the GOP presidential contender is unmarried. Last week, in criticizing the nuclear deal with Iran, Kirk told a radio station that Obama was trying "to get nukes to Iran."

Although Kirk endured criticism from Democrats after making those and other statements, Republicans rushed to his defense Wednesday after one of their own raised concerns about the impact Kirk's comments could have on the party's election fortunes.

"I do not believe he will be a U.S. senator in 2017 and, as top of the ticket, he could cause collateral damage" to other Republicans on the ballot, Chicago businessman and campaign donor Ronald Gidwitz told Crain's Chicago Business, referencing what he called "misstatements" by Kirk.

Gidwitz, a former candidate for Illinois governor, later retracted the statement and said Kirk was the best candidate for the job. He declined to elaborate when contacted Wednesday by The Associated Press.

Kirk also previously suggested that federal bureaucrats were collecting personal data on Supreme Court justices and members of Congress. And, last winter, he called for putting "a number of coffins" outside Democrats' offices if a terrorist attack resulted from a government shutdown over a budget dispute.

Nick Kachiroubas, a DePaul University political scientist, said Gidwitz's critical comments raise the possibility of a primary election challenge from a conservative, although moderates like Kirk usually have a better chance to win statewide in Illinois, where Democrats still dominate the representation in the Legislature and U.S. House.

"That's part of the reason we haven't seen a more credible challenger is that they (conservatives) know they might not have the seat as a conservative seat, they have it at least as a Republican seat, and the conservatives control more of the national agenda at this point," Kachiroubas said.

Pat Brady, the former Illinois Republican Party chairman, said the party needs to "rally around" Kirk.

"He's been a great senator," Brady said. "He's been a leader on national security issues. He's really tried to be bipartisan, which, in Illinois, is important. He's been good on the environment. He was way out front on the marriage equality issue, so he fits the state perfectly, and he's a great candidate for us."

Illinois Gov. Bruce Rauner and Tim Schneider, current chairman of the Illinois Republican Party, also expressed support for Kirk's re-election bid in statements late Tuesday.

Kirk has received widespread financial support, and Senate Majority Leader Mitch McConnell, a Kentucky Republican, has been working to get him re-elected.

Kachiroubas said that even though Gidwitz retracted his statement, a Democratic challenger would be able to use Gidwitz's words against Kirk.

A spokesman for U.S. Rep. Tammy Duckworth, a prominent Democrat in the race, declined comment. However, her campaign has launched an online ad entitled "Mark Kirk's Outrageous Statements," highlighting not only the recent comments, but exaggerations he told about his military record that became part of his 2010 campaign for Senate.

Andrea Zopp, a former federal prosecutor also preparing a Democratic run, released a statement saying that Republicans, regardless of who they nominate, are the "fundamental problem" for failing to endorse issues important to middle-class families.

Kent Redfield, a political scientist with the University of Illinois at Springfield, said Kirk could survive the criticism.

"If there are no more questionable statements from Kirk and he's very disciplined and very measured in all his public comments between now and the election, something said in the spring or summer of 2015 isn't going to make any difference," Redfield said.

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Contact Political Writer John O'Connor at http://twitter.com/apoconnor