After averting the fiscal cliff by reaching a deal with Republican leaders on New Year’s Eve, President Obama appears set to wade into a new fight with Congress next week by nominating former Nebraska GOP senator Chuck Hagel to be the next secretary of defense.

Key Democrats working closely on the nomination process tell The Daily Beast that the president is expected to announce the Hagel selection Monday or Tuesday. These sources also say Obama did not decide on Hagel until this week, after weighing Ash Carter, the current deputy secretary of defense, and Michèle Flournoy, a former No. 3 at the Pentagon, for the job.

When Hagel’s name first floated last month as a possible successor to Leon Panetta at the Pentagon, it drew scrutiny from former Senate Republican colleagues like Lindsey Graham, and even some Democrats like Eliot Engel, a House representative from New York who is the most senior Democrat on the House Foreign Affairs Committee.

Sen. John Cornyn, a Republican from Texas, told The Daily Beast Friday, “Chuck Hagel’s opposition to Iranian sanctions and support for direct, unconditional talks with its leaders is both at odds with current U.S. policy and a threat to global security. To make matters worse, he has called for direct negotiations with Hamas. The worst possible message we could send to our friend Israel and the rest of our allies in the Middle East is Chuck Hagel.”

But Hagel has also attracted support from journalists, pundits, and former national-security officials known for their activism against what they perceive to be a vast pro-Israel lobby. In addition, a Washington lobbying firm, the Podesta Group, has started a $35,000 advocacy campaign for the former Nebraska lawmaker, according to Foreign Policy magazine.

The case for Hagel is that he is a combat veteran who won a Purple Heart while serving in Vietnam. The next secretary of defense will preside over a period of budget austerity when the military will transform from a force capable of waging two land wars at once to a stealth military capable of counterterrorism missions.

Steve Clemons, a senior fellow at the New America Foundation and friend of Hagel’s, said, “I think the fundamental issue is the White House has a number of compelling candidates that it could have chosen, that it has elected to bring someone who is the first combat veteran in over 30 years to head the Pentagon.”

While Hagel has a reservoir of support from elite journalists, foreign-policy intellectuals, and former government officials, he is not beloved by many other interest groups, including the pro-Israel lobby, the gay-equality lobby, and even Armenian-Americans.

The result has been an intense battle over Hagel even before any nomination has been announced. The ex-senator’s supporters have decried what they say is a smear campaign orchestrated by the likes of William Kristol, the editor of The Weekly Standard, and Josh Block, the head of the Israel Project, a pro-Israel nonprofit. Hagel’s critics say his defenders have not addressed concerns raised about the man’s record as a senator that suggest he holds positions out of sync with Obama on issues like Iran and Hamas.

When he was a senator, Hagel often made it a point to not sign letters circulated by the American Israel Public Affairs Committee. He voted against resolutions proposing sanctions against Iran and designating Iran’s Revolutionary Guard Corps as a terrorist group. In 2009, when he was out of office, Hagel signed a letter urging the Obama administration to encourage the Palestinian Authority to form a unity government with Hamas, an organization that calls for the destruction of Israel in its charter.

One Democratic Party official working on the nomination said any discrepancies between Hagel’s positions as a senator more than four years ago and the president’s will be handled in the confirmation process. “The president has made crystal clear what his policies are on issues like Iran and Israel, and Senator Hagel will of course have a chance to discuss those issues in a confirmation hearing,” this person said.

Clemons said he expects Hagel will meet with members of the pro-Israel and gay-equality communities to address concerns these groups have had about him. Overall, Clemons said he is pleased Obama is going with Hagel. “This shows a maturity and resolve of the president to pick someone based on core rationale as opposed to blowing with the winds,” he said. “The fact that Obama is willing to take on some of the communities that have expressed concern shows the president is maturing and becoming more self-confident in his national-security and foreign-policy vision.”