Paul Ryan: I'm not running for president

Republican Rep. Paul Ryan of Wisconsin said Monday that despite calls from some quarters to enter the presidential race, he won't be seeking the Republican presidential nomination in 2012.

"While humbled by the encouragement, I have not changed my mind, and therefore I am not seeking our party's nomination for President," Ryan said in a statement. "I remain hopeful that our party will nominate a candidate committed to a pro-growth agenda of reform that restores the promise and prosperity of our exceptional nation. I remain grateful to those I serve in Southern Wisconsin for the unique opportunity to advance this effort in Congress."

Ryan, chairman of the House Budget Committee, is the author of the House GOP's controversial budget plan that included significant cuts to Medicare. That plan - along with the perception that he is an effective communicator, particularly when making the case for entitlement reform - has fueled calls from fiscal conservatives for Ryan to enter the race.

The conservative Weekly Standard magazine reported last week that Ryan was "strongly considering" a White House bid and has spoken with Republican strategists about his prospects. Ryan has expressed frustration with the current GOP presidential field, saying in an interview last week that he has "yet to see a strong and principled articulation of the kind of limited government, opportunity society path that we would provide as an alternative to the Obama cradle-to-grave welfare state."

Ryan's apparent decision to stay out of the race leaves four names on the list of prominent Republicans seen as possible late entrants into the race: Former Alaska Gov. Sarah Palin, New Jersey Gov. Chris Christie, former New York Mayor Rudy Giuliani and former New York Governor George Pataki.

Palin has said she is actively considering a run, and last week she released a campaign-style video about her recent trip to Iowa. Christie has explicitly said he won't enter the race, though he has met with donors about a possible run. Giuliani has traveled to New Hampshire to explore a bidand said he will decide by September, while sources said over the weekend that Pataki is "seriously considering" entering the race.