WASHINGTON — A House panel has started debate on a bill co-sponsored by an Idaho congressman that would, if enacted, mark a major step in enacting President Trump’s promised crackdown on undocumented immigrants.

The House Judiciary Committee spent about two hours Thursday on the Davis-Oliver Act, which is being sponsored by committee chairman U.S. Rep. Bob Goodlatte, R-Va., and U.S. Rep. Raul Labrador, R-Idaho. The committee plans take it up again Tuesday.

Named after California police officers Michael Davis Jr. and Danny Oliver, who were murdered by an undocumented immigrant in 2014, the wide-ranging bill would take away some federal grants from local governments that refuse to cooperate with immigration authorities and let the victims of crimes committed by undocumented immigrants in “sanctuary” jurisdictions sue the municipality. It would let states and local governments both help enforce immigration laws and enact immigration laws of their own as long as they don’t conflict with federal ones, and it would make it a misdemeanor to be in the country illegally — being here without documentation is currently a civil violation, not a criminal one.

Passing the bill would let states pass laws such as SB 1070 in Arizona, which required police to check the immigration status of people they stopped. The U.S. Supreme Court struck down parts of this law in 2012, one of the grounds being that it conflicted with federal policy.

“Mr. Labrador’s bill gives states and localities the explicit congressional authorization the Supreme Court requires to (let them) enact and enforce their own immigration laws,” Goodlatte said.

Labrador called respect for the law a “foundational principle” of the United States that, he said, was undermined by President Barack Obama’s immigration policies.

“They believe that enforcing the law threatens public safety,” Labrador said of the bill’s opponents. “That is the most preposterous and outrageous argument that I’ve ever heard, and I think it’s time we start enforcing immigration laws.”

The Democrats on the committee said it would stigmatize illegal immigrants as being a danger when some studies have shown they are less likely to commit crimes than the native-born, as well as discouraging them from cooperating with authorities if they are crime victims or witnesses.

“The way to keep the cities and counties safe is that everybody is free to point out the criminal and the crime,” said U.S. Rep. Sheila Jackson Lee, D-Texas.

Several Democrats said the bill would create a “deportation force” desired by President Donald Trump and his chief strategist Steve Bannon, the former head of the right-wing nationalist Breitbart website. Passing this law is a goal of Bannon’s — it was on a to-do list on his whiteboard.

“This bill gives Trump and Bannon the legislative authority to establish their massive deportation force and would … turn our communities into police states overnight,” said U.S. Rep. Zoe Lofgren, D-Calif.

The committee killed two amendments offered by the Democrats. One would have gutted the bill by striking the section dealing with state and local enforcement. The other would have removed the section making being here illegally a misdemeanor.

U.S. Rep. Jerry Nadler, D-N.Y., said this would make criminals out of people who came here as children, accidentally overstayed a visa or even tourists who missed a flight. Labrador said it was a needed part of the bill.

“This is a crucial provision to ensure that (Immigration and Customs Enforcement) can arrest, prosecute and actually deter illegal immigration,” he said.

If the bill makes it out of committee it will go to the full House, where leadership would decide when or whether it comes to a vote.