Washington Post columnist says Rahm Emanuel considering run for Chicago mayor. White House says not so.

The Washington Post’s Sally Quinn–a columnist who is the voice of the Washington establishment–on Tuesday wandered into the Chicago precincts of the Obama White House. She’s floating White House Chief of Staff Rahm Emanuel for Chicago mayor–and predicting he will stay on the job for only 18 months.

A White House aide said in response to Quinn, “we are saying the same thing we’ve been saying about this since this rumor started more than a year ago: “Rahm is 100% focused on the job at hand – serving President Obama as his Chief of Staff.”

Quinn’s Emanuel nugget is buried in a column where she called for White House Social Secretary Desiree Rogers–and Secret Service Director Mark Sullivan– to step down in the wake of three people crashing the Nov. 24 Obama White House state dinner for the Prime Minister of India. Rogers is a close friend of the Obamas and White House senior advisor Valerie Jarrett.

Quinn’s column was triggered by the Secret Service announcement on Tuesday that Tareq and Michaele Salahi were not the only crashers at the party; on Monday came the news of a third crasher. Before the State Dinner, the third crasher identified in another Post story as Carlos Allen, a party planner with links to the Salahis– joined a delegation of Indian CEO’s at the Willard Hotel, near the White House, in a group assembled by the State Department. The Secret Service cleared the group through security at the hotel; the State Department then drove them to the White House, not aware that one of the men in the group was not on the guest list.

Quinn suggested that Emanuel was not pressuring Rogers to resign because of what she presumed were his mayoral ambitions.

“Emanuel, the most political animal in this town, also should understand that keeping Rogers on as social secretary reflects upon the president’s judgment. It’s possible that he has other considerations,” Quinn wrote. “Emanuel is said to have told people that the chief-of-staff role is an 18-month job and that he is considering a run for mayor of Chicago. And Rogers is a major social and political player in the Windy City.”

Emanuel is finishing his first year as chief of staff. He moved his family to Washington from their North Side home this summer. He gave up a safe House seat that could have led him to be Speaker of the House to join the Obama administration.

Mayor Richard Daley, 67, is up for re-election in 2011–and has not said if he will run again–but if the health of wife Maggie permits–it’s hard to see Daley–who’s had one of the worst years of his 20 years in City Hall– quitting while it is perceived he is down. In December, 2010, Daley will be Chicago’s longest serving Chicago mayor–passing the mark of his father, Richard J. Daley.

Emanuel is a Daley loyalist. He would never run against the mayor. Emanuel won his House seat with the help of Daley’s political army. And while Emanuel is a superpower in Washington, his standing in D.C. would not translate into an automatic clearing of the field if he ran for mayor. There are a lot of Chicago political heavyweights who have been waiting a long time for Daley to step down or retire.