Louisiana Senator Mary Landrieu has said she personally backs gay marriage but is obliged to represent the views of her constituents.

Landrieu is among the final four Democratic senators who remain opposed to marriage equality after a flurry of senators shifted their public stance in recent weeks. The other three holdouts are Mark Pryor of Arkansas, Joe Manchin of West Virginia and Tim Johnson of South Dakota.

In comments to CNN, Landrieu said she personally believes “people should love who they love and marry who they want to marry,” but that her obligation is to the people of Louisiana who elected her to Congress.

“My state has a very strong constitutional amendment not only against gay marriage but against gay partnerships,” she said. “So I'm looking at the people of Louisiana trying to represent their interests.”

On Thursday, Florida Senator Bill Nelson said that he could not discriminate against gays because “The Lord made homosexuals as well as heterosexuals.” The following day, Indiana Senator Joe Donnelly said that backing the institution was “the right thing to do” and North Dakota Senator Heidi Heitkamp said that the “importance of family is enduring” in announcing her support.

Fifty-three senators support marriage equality, including two GOP senators: Rob Portman of Ohio and Mark Kirk of Illinois.