Attorney General Rob Bonta said he would defend birthright citizenship following an executive order by President Donald Trump, as California officials gear up for what is expected to be many legal challenges involving the new administration.

California Attorney General Rob Bonta announced his office would be joining 17 other states in suing the federal government over the newly inaugurated President Donald Trump’s executive order ending birthright citizenship for those born in the country.

The lawsuit: Birthright citizenship is enshrined in the U.S. Constitution’s 14th Amendment, Bonta said at a Tuesday news conference. He called Trump’s executive order “blatantly unconstitutional” and “unAmerican,” adding, “I’ll see you in court.”