So much logistical planning goes into a presidential foreign trip that it's almost unthinkable to cancel them.
Almost - but not out of the question.
Because getting a health care bill enacted is his top priority, President Obamastarting Sunday to Indonesia, Australia and Guam.
"Passage of health insurance reform is of paramount importance, and the president is determined to see this battle through," said spokesman Robert Gibbs in announcing the decision to postpone the trip until sometime in June.
Had he left as scheduled on Sunday morning, he would been out of town when the House vote on the health care bill takes place, which could be as early as Sunday afternoon. And should key members need additional presidential arm-twisting or jaw-boning, the best Mr. Obama could have done is a phone call from Air Force One. The White House decided that wasn't good enough with his top legislative priority at stake.
"We greatly regret the delay in the trip but at the same time have told the leaders this is an important priority for the president, and we'll reschedule that trip for June," Gibbs told reporters.
Cancellations of presidential trips abroad are rare but not unprecedented.
In November 1998, President Clinton scrapped his long-scheduled trip to the Asia Pacific Economic Cooperation summit in Malaysia because of a U.N. showdown with Iraq's Saddam Hussein over weapons inspectors. He sent Vice President Al Gore in his place.
Iraq was still at the center of a crisis four years later, when President George W. Bush scrubbed a five-nation trip to Africa in January 2003, two months before the U.S.-led invasion of Iraq. He embarked on the trip in July of that year.
Mr. Bush also scrubbed a May 5 visit that year to Canada and talks with then-Prime Minister Jean Chretien. The White House said the demands of the war in Iraq would keep the president from visiting Ottawa, though there was new friction with Chretien because of his decision to keep Canada out of the war.
Mr. Obama personally called Australia's Prime Minister Kevin Rudd and Indonesia's President Susilio Bambang Yudhoyono to explain his decision and assure them of his desire to visit later in the year.
What the White House could not explain is how much the cancellation of a major presidential overseas trip would cost taxpayers in un-reimbursed expenses for hotels, aircraft, vehicles and personnel costs.
The cancellation could also cost members of the White House press corps thousands of dollars per person for canceled hotel rooms, conference rooms and a chartered airliner.
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Mark Knoller is a CBS News White House correspondent. You can read more of his posts in Hotsheet here. You can also follow him on Twitter here: http://twitter.com/markknoller.