(Charles Dharapak – AP)

Mitt Romney is throwing his support behind Elise Stefanik's bid to represent New York's 21st congressional district, giving a former campaign aide a boost in a contested GOP primary.

"Elise understands the needs of small businesses and how to grow the local economy. She is a person of integrity. Every campaign is different, but values don’t change," Romney said in a statement Tuesday.

Stefanik is a former Bush administration aide who worked on Rep. Paul Ryan's 2012 vice presidential debate prep team. Ryan has endorsed Stefanik and plans to campaign with her on June 2. Stefanik faces businessman Matt Dohney in the battle for the GOP nomination.

President Obama defeated Romney 52 percent to 46 percent in the upstate 21st district, which is represented by retiring Rep. Bill Owens (D).