A federal judge on Friday struck down Missouri's ban on gay marriage as unconstitutional.

“[T]he Court holds the prohibition on same-sex marriage violates the Fourteenth Amendment's Due Process Clause,” U.S. District Judge Ortrie D. Smith wrote in his 18-page ruling.

“The Court does not take lightly a request to declare that a state law is unconstitutional,” Smith added elsewhere. “Statutes are passed by the duly elected representatives of the people. Article 1, section 33 constitutes the direct expression of the people's will. It is not on a whim that the Court supplants the will of the voters or the decisions of the legislature.”

“But it should not be forgotten that the Constitution is also an expression of the people's will. Indeed, it is the paramount expression of the people's will; it cannot easily be cast aside or circumvented by a vote of the citizens of a single state.”

Plaintiffs in the case are two gay couples, Angela Curtis and Shannon McGinty and Kyle Lawson and Evan Dahlgren, who wish to marry in Missouri but were denied marriage licenses in June.

The ruling comes two days after a state judge knocked down Missouri's ban, allowing gay couples to begin marrying in St. Louis, and a month after a judge in a separate case ordered officials to recognize the out-of-state marriages of gay couples.

Smith stayed his ruling pending an appeal.

Attorney General Chris Koster said in a statement that his office would appeal the ruling to the Eighth Circuit Court of Appeals.

Marc Solomon, national campaign director of Freedom to Marry, applauded Smith's ruling in a statement.

“Today’s victory in Missouri marks the third consecutive win in the ‘Show Me’ state in just over a month, with all three judges affirming that marriage discrimination is unconstitutional,” said Solomon, a Kansas City native. “We encourage Attorney General Chris Koster not to appeal the ruling so that Missouri becomes the next state where loving and committed couples can share in the joy and dignity of marriage. Today’s ruling adds to the powerful momentum of victories from a bipartisan array of federal and state judges as we work to secure the freedom to marry nationwide.”

(Ruling provided by Equality Case Files.)