In an op-ed in the San Francisco Chronicle published before the commerce department's decision, Mr Becerra said adding the citizenship question would be "an extraordinary attempt by the Trump administration to hijack the 2020 census for political purposes".
The decision by the Commerce Department followed a request from the U.S. Department of Justice to reinstate the citizenship question.
But California isn't the only state that has opposed the citizenship question.
In an eight-page memo Commerce Secretary Wilbur Ross says the Justice Department has requested that the census ask who is a citizen in order to help determine possible violations of the Voting Rights Act, to help enforce that law... Becerra said the citizenship question is unconstitutional and would violate federal statutes. "Now, in one fell swoop, the US Commerce Department has ignored its own protocols and years of preparation in a concerted effort to suppress a fair and accurate census count from our diverse communities".
The agency said the citizenship question will help to ensure enforcement of the Voting Rights Act, a 1965 law created to ensure minority access to the polls.
Attorney General Maura Healey's office said Tuesday that the Democrat will join a multi-state lawsuit led by New York's attorney general.
Critics, including Gov. Andrew Cuomo and state Attorney General Eric Schneiderman, view the question as an attack on immigrants. Rep. Grace Meng, D-N.Y., said she would introduce legislation to stop the question from being included in the census.
The Trump administration has provoked threats of lawsuits and a backlash from senior Democrats after deciding to reinstate a controversial question about citizenship status in the next USA census. "Make no mistake - this decision is motivated purely by politics". The question has not been a part of the census since World War II. They will argue that as a result, an undercount of population in states where large immigrant communities live will impair fair representation.
"This question will lower the response rate and undermine the accuracy of the count, leading to devastating, decade-long impacts on voting rights and the distribution of billions of dollars in federal funding", Holder said.
The question has not been on the full decennial census since the 1950s, but does appear on the yearly American Community Survey administered by the Census Bureau to give a fuller picture of life in America and the population.
"Counting the number of US citizens in the country should be a high priority of the census, and the only way to get an accurate count is to add a question about citizenship to the census itself", Cotton said.
The department said: "Secretary Ross determined that obtaining complete and accurate information to meet this legitimate government goal outweighed the limited potential adverse impacts".
President Donald Trump has argued, without providing evidence, that millions of illegal immigrants voted in the 2016 presidential election.
California would be particularly hard-hit by the change, due to its high proportion of foreign-born and undocumented residents, as Becerra's lawsuit states.
And as it is, the Census Bureau itself estimated that its 2010 count undercounted the Latino population in the U.S. by 1.5 percent and the black population by 2.1 percent, numbers that experts say will be much worse with the new question. Galvin called the decision an attempt to suppress the count in states such as MA that have large immigrant populations.