Commerce Secretary Wilbur Ross at the White House on March 6. (Jabin Botsford/The Washington Post)

Commerce Secretary Wilbur Ross acted in “bad faith,” broke several laws and violated the constitutional underpinning of representative democracy when he added a citizenship question to the 2020 Census, a federal judge ruled Wednesday.

In finding a breach of the Constitution’s enumeration clause, which requires a census every 10 years to determine each state’s representation in Congress, the 126-page ruling by U.S. District Judge Richard Seeborg in San Francisco went further than a similar decision on Jan. 15 by Judge Jesse Furman in New York.

The Supreme Court has already agreed to review Furman’s narrower decision, with arguments set for April 23, but may now need to expand its inquiry to constitutional dimensions.

The Commerce Department did not respond to requests for comment.

The administration has been on the losing end of scores of court decisions involving immigration issues since President Trump took office. But the census case has taken on special significance because it strikes at the heart of the United States’ form of government and because of what Seeborg described as a “strong showing of bad faith” by a Cabinet secretary who, influenced in part by White House advisers, tried to conceal his motives.

The cases against Ross have been brought by jurisdictions with significant immigrant populations. Only two have completed trials, the case heard by Furman and brought by 18 states led by New York, and Wednesday’s challenge, initiated by the state of California and combined with a suit brought by the city of San Jose.

Unable to find any expert in the Census Bureau who approved of his plan to add the citizenship question, Seeborg wrote, Ross engaged in a “cynical search to find some reason, any reason” to justify the decision.

He was fully aware that the question would produce a census undercount, particularly among Latinos, the judge said.

That would have probably reduced the representation in Congress — and thus in the electoral college that decides the presidency — of states with significant immigrant populations, notably California.

Because census data is used to apportion distribution of federal funds, an undercount would also have cheated these same jurisdictions, the judge said.

Seeborg, like Furman, found after a trial that Ross misrepresented both to the public and Congress his reasons for adding the citizenship question last March. Ross claimed he was acting at the request of the Justice Department in the interest of enforcing the Voting Rights Act.

In reality, the “evidence establishes” that the voting rights explanation was just “a pretext” and that Ross “acted in bad faith” when he claimed otherwise.

He pursued the citizenship question after hearing from then-White House adviser Stephen K. Bannon and Kris Kobach, the vice chair of Trump’s now-disbanded voting fraud commission.

Apart from violating the ­Constitution, Seeborg ruled, the Commerce Department breached the Administrative Procedure Act by acting “arbitrarily and capriciously” and violated Census Act restrictions on modifying questions.