The battle over President-elect Donald Trump's attorney general nominee, Alabama Sen. Jeff Sessions, is heating up ahead of what promises to be a deeply contested confirmation hearing next year.

Groups on the left are ratcheting up their criticism of Sessions on issues such as immigration, criminal justice and voting rights while those supporting him are unveiling the first component of what is expected to be a vigorous campaign in his favor. His confirmation hearings are scheduled for January 10 and 11 before the Senate Judiciary Committee.

The conservative Judicial Crisis Network on Thursday launched a website, ConfirmSessions, accompanied by a six-figure ad-buy touting the Alabama senator as someone who will enforce the law.

The digital ads, targeting the Washington, D.C. market, show clips of Trump praising Sessions and highlighting his experience as U.S. attorney in Alabama and then senator of the southern state.

“From his time as U.S. Attorney to his tenure as attorney general for the state of Alabama, Jeff Sessions successfully prosecuted drug and violent criminals, corrupt politicians and white collar offenders and his record shows an absolute commitment to equal justice under law by putting the people first — not powerful special interests,” said Carrie Severino, chief counsel of the Judicial Crisis Network.

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Now the battle lines are being drawn over his nomination.

Sessions has a controversial past on issues of race and immigration, including his failed confirmation of a federal judgeship 30 years ago largely because of racially insensitive remarks.

In the 1980s, Sessions was considered for a Ronald Reagan-appointed federal district judgeship in Alabama, but was blocked by the Senate after a black former deputy, Thomas Figures, accused him of making racially insensitive statements. Figures said that Sessions called him "boy" and had once warned him to be careful about what he said to "white folks." Sessions denied the remarks under oath at the time. In addition, U.S. Attorney E.T. Rolison and Assistant U.S. Attorney Ginny Grenade – two people Figures said were in the room at the time of the alleged remarks -- signed affidavits saying they did not hear Sessions call Figures "boy." Grenade signed the affidavit in 1986 and Rolison signed one on December 8 of 2016.

Figures, a former assistant U.S. Attorney in Alabama, also testified that, during a 1981 murder investigation tied to the Ku Klux Klan, Sessions commented that he "used to think they [the KKK] were OK" until he found out some were "pot smokers." Sessions claimed he had been joking.

Now, progressives are pouncing.

The progressive group People for the American Way has drawn attention to missing information that Sessions failed to include in a vast questionnaire that he is required to fill out ahead of his confirmation hearings.

In a 10-page memo that outlines Sessions’ omissions, PFAW notes that in response to questions about his public statements, Sessions listed 48 opinion articles that he wrote. But the group found 43 more. He also didn’t include any of the 60 press releases from 2003 and 2004, including one on the Federal Marriage Amendment, according to the group. Nor did Sessions make mention of his failed nomination to be a federal judge from 20 years ago.

“Sessions’ questionnaire is grossly incomplete — we’ve found hundreds of relevant missing documents in just a few days,” said Marge Baker, executive vice president of People for the American Way. “It’s ridiculous to think that the Senate could possibly give thorough consideration to a nominee with this many holes in his questionnaire.”

In response, Sessions submitted two additional pages of information on Thursday, including the listing of his judicial nomination.

Sen. Dianne Feinstein, D-California, the incoming ranking member of the Senate Judiciary Committee, is urging Republicans to delay the confirmation hearing.

In a letter to the top Republican on the Senate Judiciary Committee, Sen. Chuck Grassley of Iowa, Feinstein suggested that a delay of the hearings might be necessary for two reasons: Sessions' incomplete questionnaire and the reams of information that the committee must investigate in less than a month. She noted that Sessions has more than 30 years of public service and public statements that must be analyzed, and the 150,000 pages of information he handed over, while not a complete accounting, is too much to assess before January 10.

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“Staff must have sufficient time to do the due diligence on any nominee for this vital position — and this due diligence will likely take longer than the review for recent, prior nominees who had less materials to analyze,” Feinstein wrote.

Drew Courtney, communications director for PFAW, said: “No matter who the nominee is, the confirmation process for an attorney general needs to be taken seriously; Given Donald Trump’s dismissive attitude towards the Constitution, that’s doubly true this year. Senator Grassley is doing the country a real disservice by trying to rush the process.”

But Sen. Grassley has indicated that he has no intention of postponing the hearings. "It is no surprise that Senator Sessions’ twenty years of service as our colleague—not to mention his service in the Department of Justice and to the State of Alabama—yielded an extensive record," Grassley wrote in a letter responding to Feinstein.

Severino defended Sessions in a statement. “Senator Sessions has turned over more material than any nominee in history and is well known to the senators. Liberals are scrambling to delay because they don't want an attorney general who puts the American people and the rule of law ahead of political agendas,” Severino said.

This first battle is likely a sign of more conflicts to come over Sessions' nomination as the hearings approach.