Loretta Lynch faces the Senate Judiciary Committee on Wednesday.
Washington CNN  — 

Attorney General nominee Loretta Lynch is a career prosecutor who spent her career notching high-profile courtroom victories and climbing to the top of the legal ranks of Brooklyn’s U.S. attorney’s office.

But on Wednesday, she’ll walk into a Senate Judiciary Committee where the newly Republican-controlled chamber is seething with anger at President Barack Obama’s administration, and looking for outlets to express it.

READ: Obama nominated Loretta who?

Specifically, the GOP is looking for opportunities to combat Obama’s executive overhaul of U.S. immigration rules. They’ll seek answers on how the Justice Department will treat new local laws that permit marijuana use. They’ll ask questions about U.S. military interventions overseas.

Whether she’s confirmed as Eric Holder’s replacement could largely depend on her answers. Holder had a tempestuous relationship with Congress, particularly House Republicans, and many observers will be watching how Lynch carries herself during the expected scrutiny.

The biggest potential hurdle could be immigration. Louisiana Republican Sen. David Vitter said Lynch’s nomination would be an opportunity to swing back at Obama for his post-midterm election executive moves to forestall some deportations.

“We’ll have the opportunity to push back on executive amnesty with one of our first major battles: the attorney general nomination,” Vitter said in a statement in December. “The attorney general is one of the linchpins to Obama’s amnesty plan, and I’ll be working to get the new Congress to block this nomination.”

Lynch could also face questions about the Justice Department’s investigations of police departments – particularly since her U.S. attorney’s office is leading the investigation into the police killing of an unarmed black suspect in Staten Island.

The issue isn’t new to Lynch, who is perhaps best known for her prosecution and conviction of two New York City police officers who sodomized the Haitian immigrant Abner Louima after arresting him outside a Brooklyn nightclub in 1997.

Lynch wouldn’t need many Republican supporters to win confirmation, since – unlike most legislation – the Senate currently only requires 51 votes for some presidential nominees. She’s likely to be backed by all the chamber’s Democrats, led by New York Sens. Chuck Schumer and Kirsten Gillibrand.

White House press secretary Josh Earnest has urged Congress to confirm Lynch before Feb. 16, though Senate Republicans appear unlikely to move that quickly.

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Wednesday’s hearing will also be the first major test for new Senate Judiciary Committee Chairman Chuck Grassley, the Iowa Republican who took over after the GOP claimed the Senate in November.

“I have every confidence that Ms. Lynch will receive a very fair, but thorough, vetting by the Judiciary Committee,” Grassley said in a statement after Lynch was nominated.

“U.S. Attorneys are rarely elevated directly to this position, so I look forward to learning more about her, how she will interact with Congress, and how she proposes to lead the department,” he said. “I’m hopeful that her tenure, if confirmed, will restore confidence in the Attorney General as a politically independent voice for the American people.”