WASHINGTON – Colorado U.S. Sen. Michael Bennet joined a group of Senate colleagues this week in introducing a bill to block the Trump administration from asking residents about their citizenship on the upcoming U.S. census.

The Trump administration wants to ask all voting-age U.S. residents about the status of their citizenship in the 2020 census.

Administration officials say they need the question to enforce the Voting Rights Act, which prohibits discrimination that might interfere with minorities’ right to vote.

Trump’s critics say the citizenship question would result in an undercount on the census because immigrants would avoid responding to it.

They also say immigrants most often are Democrats, which means Republicans would emerge with more political clout.

“The federal census is a Constitutionally mandated, nonpartisan process by which every person in this country counts,” said Bennet, a Democrat, in a statement. “Politicizing this tool will have severe consequences for immigrant communities in our country. We should be working to make this process more transparent and accurate, not using scare tactics to prevent people from participating.”

Additional criticism of the citizenship question came from attorneys general of 12 predominantly Democratic states. They say they will sue to prevent the question.

California’s attorney general already filed a lawsuit in federal court. New York’s attorney general is leading the joint effort by his colleagues in other states.

Colorado Attorney General Cynthia Coffman, a Republican, has given no indication yet that she would join the lawsuit. Her spokeswoman did not respond to an email inquiry about the attorney general’s position on the census question.

However, Gov. John Hickenlooper, a Democrat, co-signed a letter with 19 attorneys general earlier this year asking the U.S. Commerce Department to exclude any citizenship questions on the census.

The Commerce Department ignored their plea, saying in a statement this week that citizenship would be on the next census for the first time since 1950.

“I find that the need for accurate citizenship data and the limited burden that the reinstatement of the citizenship question would impose outweigh fears about a potentially lower response rate,” Commerce Secretary Wilbur Ross wrote in a memo to his subordinates.

A 2017 Pew Research Center study found that Denver, Chicago, Seattle, Washington, D.C. and four California cities all have 100,000 to 400,000 illegal immigrant residents. New York City and Los Angeles each have more than 1 million, the study reported.

The bill Bennet co-sponsored says it would “prohibit the Secretary of Commerce from including any census question regarding United States citizenship or immigration status.” It is called the Every Person Counts Act of 2018.

The U.S. Constitution requires that all residents of the United States be counted every 10 years.

The government uses census information to determine how it allocates grants and services, such as where schools should be built, how infrastructure funds should be spent and how public welfare benefits should be distributed. The census also determines how voting districts are drawn.

A spokesman for Bennet described a citizenship question as intimidation that would depress participation in the census by Colorado’s immigrant communities.

Colorado U.S. Rep. Diana DeGette, D-Denver, was an outspoken critic this week of the Trump administration’s census plans.

She accused Trump of trying to rig the 2020 Census in a way that undermines residents’ civil rights, leads to cuts in funding for important federal programs and distorts redistricting of voting districts.

“The Constitution doesn’t say that only citizens count,” DeGette said “This politically motivated attempt to rig the census will drive people away from taking part for fear that their citizenship status could be used against them or their families. That, in turn, would deprive entire communities of fair representation in Congress and in the statehouse and could starve the programs that serve their needs for housing, health care, education and more.”

If immigrants are discouraged from participating in the census, the federal government would “make decisions that won’t truly represent the needs and rights of everyone in this country,” DeGette said.

Colorado U.S. Rep. Mike Coffman, R-Aurora, referred to the citizenship census question only in generalized terms.

“The U.S. Census is an important tool to ensure all those who live in our country are counted and thus properly represented,” he said. “I don’t see any actions that are counter to this purpose as useful, nor something I would support.”