Updated

Chuck Hagel likely would face opposition from both liberals and conservatives for his past stances and comments if President Obama nominates the former Republican senator for the top spot at the Pentagon -- as sources tell Fox News is expected, as early as next week.

Hagel’s name has been floated around Washington for weeks as Obama's top choice for the next secretary of defense, but pro-Israel groups, conservatives and gay rights organizations all have raised objections, respectively citing comments he made about a gay former diplomat and his views on Iran and Israel.

Confirmation hearings wouldn't be easy.

Sen. Marco Rubio, R-Fla., has signaled he’ll move to block the bid unless Hagel withdraws his opposition to the U.S. trade embargo against Castro’s Cuba.

Other lawmakers have expressed concern over Hagel’s resistance to sanctions against Iran and to the designation of Hezbollah as a terrorist group.

Hagel went on an apology spree in late December and back-peddled on comments he made about the sexual orientation of an ambassador candidate during a 1998 interview, but the country’s largest gay and lesbian groups said they were unimpressed and questioned his sincerity.

The controversy stems from comments he made during a debate over the nomination of James Hormel to be ambassador to Luxembourg. Hagel had said Hormel was “openly aggressively gay.”

“My comments 14 years ago in 1998 were insensitive,” Hagel said in a written statement. “They do not reflect my views or the totality of my public record, and I apologize to Ambassador Hormel and any LGBT Americans who may question my commitment to their civil rights.”

The White House has had to come to the former Nebraska senator's defense multiple times since word leaked that he may be considered for a spot in Obama’s Cabinet.

Lawmakers on both sides of the aisle have spoken out against his bid.

Indiana Sen. Dan Coats, a Republican, blasted Hagel in an interview with radio host Tom Rose.

"Chuck has alienated an awful lot of people," Coats said. "There have been grace concerns about this possible nomination among Republicans and among people who know and have served with Chuck Hagel. We watched Chuck take positions that are, frankly, many of them are to the left of Barack Obama."

He continued: "Hagel has moved from a conservative Republican coming out of Nebraska to someone that looks like they are out of the most leftist state in the country and exceeding even a lot of Democrats, who also have concerns about his ideology and where he is coming from. I think it would be a mistake for the president to put his nomination up."

When asked about the pulse of Republicans on Hagel, Sen. Linsey Graham, R-S.C., told Chris Wallace on Sunday, "I can tell you there would be very little Republican support for his nomination. At the end of the day, there will be very few votes.”

But there are some supporters and they point to his infantry service in Vietnam – where he was awarded two Purple Hearts – as proof that he’s qualified to lead the department. Hagel also served as the deputy administrator of the Veterans Administration during the Reagan administration, as well as the head of the USO, and was co-author of the 9/11 GI bill.