Updated: 9:21 p.m.

Speaker John Boehner has reportedly endorsed Maria Cino to lead the Republican National Committee, according to a letter obtained by the conservative website FrumForum.

The RNC’s 168 members arrived at Maryland’s National Harbor on Wednesday for the party’s annual winter meeting, and they will vote Friday for their next chairman.

Boehner hosted a private cocktail reception Wednesday night to thank the members for their efforts during the 2010 midterm elections. He delivered brief remarks that focused on his gratitude, but he also used the opportunity to say he personally supports Cino but understands that the selection is up to the RNC, according to members who attended the event.

Boehner opened his letter to RNC members in a similarly deferential manner. “I respect that the choice of RNC Chairman is yours alone to make,” he wrote in the letter, which FrumForum obtained from an RNC member and posted Wednesday afternoon.

He made the case for Cino before concluding, “As you meet this week to make this important decision, I respectfully ask you to support Maria Cino for RNC Chairman.”

Five candidates are in the race: current Chairman Michael Steele, Wisconsin GOP Chairman Reince Priebus, former Michigan GOP Chairman Saul Anuzis, former Missouri GOP Chairwoman Ann Wagner and Cino, who is a former RNC official. Only Priebus and Anuzis, now Michigan’s national committeeman, are current members of the committee.

Roll Call previously reported that Boehner had informally made at least one phone call on Cino’s behalf.

“I have worked closely with Maria for almost twenty years, during which time she turned around the [National Republican Congressional Committee] to usher in the first Republican majority in the House in 40 years,” Boehner wrote in the letter. “She served as CEO of the 2008 National Convention, which I chaired, and made it into one of the most successful in party history. I have learned firsthand that she is an unparalleled fundraiser and a very efficient manager of resources. She’s also exceptionally politically savvy and knows what it takes to win.”

Tricia Miller contributed to this report.