The fight over Defense Secretary Chuck Hagel's nomination was, at times, contentious. Republicans were so incensed by President Obama's nomination of another Republican, we saw a Senate minority, for the first time ever, deny an up-or-down vote to a cabinet nominee.

GOP opposition to Thomas Perez, introduced this morning as Obama's choice for Secretary of Labor, is very likely to be considerably more intense.

Capitol Hill watchers may recall that when the president nominated Perez to lead the Justice Department's Civil Rights Division, which was gutted during the Bush/Cheney era, Republicans held up the nomination for six months.

Why? Because the Justice Department had decided to dismiss a 2008 voter intimidation case involving the New Black Panther Party, and Senate Republicans blamed him for the decision -- even though Perez wasn't even a Justice Department employee at the time.

Perez was eventually confirmed, and as Adam Serwer recently explained, did some exceptional work.

[S]ince Perez took the helm [at the Department of Justice's civil rights division], the division has blocked partisan voting schemes, cracked down on police brutality, protected gay and lesbian students from harassment, sued anti-immigrant Arizona sheriff Joe Arpaio for racial profiling, stood up against Islamophobia, and forced the two largest fair-housing settlements in history from banks that discriminated against minority homeowners.

Perez says he doesn't think of civil rights as a partisan issue -- he takes pride in the fact that he was first hired by the civil rights division as a career attorney under President George H.W. Bush. But now that conservatives are working hard to roll back civil-rights-era legislation, Perez's unapologetic civil rights advocacy stands out and makes him a target for the right.

Quite right. It's not a question of whether the upcoming fight will get ugly, but rather, just how ugly it's going to get.

Indeed, it's arguably fair to say Perez is Obama's most progressive cabinet nominee to date, and enjoys the enthusiastic backing of labor unions and civil-rights organizations. But Sen. Chuck Grassley (R-Iowa) has long had a problem with the nominee.

Grassley and other congressional Republicans' latest accusation is that Perez improperly influenced a decision by the city of St. Paul, Minnesota, to withdraw its attempt to get the Supreme Court to hear a fair-housing case. The lawsuit stemmed from what the city saw as a crackdown on slumlords cynically exploiting civil rights law, and what some property owners claimed was an attempt to use building codes to displace low-income and minority renters so their neighborhoods could be gentrified. Conservatives hoped that the case would lead to a Supreme Court ruling that housing practices with a disparate impact on minorities do not violate the Fair Housing Act.

Grassley has accused Perez of convincing St. Paul to drop its federal appeal in exchange for the feds not intervening in an unrelated lawsuit, in which the city stands to lose nearly $200 million in federal grant money. That case has a racial angle too: The plaintiffs are accusing the city of misusing those federal dollars by discriminating against white workers.

It's hard to evaluate Grassley's most recent accusation because the internal documents they're supposedly based on haven't been made public. But one thing is clear: Conservatives are angry about losing an opportunity to use the Supreme Court to roll back another signature piece of civil-rights-era legislation.

Republican pundits, meanwhile, continue to focus on the New Black Panthers, in ways that don't make a lot of sense, while arguing that Perez "may as well be Hugo Chavez."

As the Republican National Committee, at least on the surface, claims to support a renewed outreach effort to Latino voters, Republican officials and their allies are already launching a vicious smear campaign against President Obama's latest Latino nominee.