http://fxn.ws/9VAQW7 Republican Rep. Joseph Cao -- in an act of either selfless concern or political expediency -- says he "must" warn President Obama that the Democratic candidate he's endorsed in the race has a history of ethical problems. The Louisiana congressman is smarting after Obama used his first general election ad to endorse Cao's opponent, Democrat Cedric Richmond. According to Cao's campaign, he had hoped Obama would endorse him considering all he did for Democrats -- like being the only Republican to cast a floor vote for the health care overhaul. "He didn't even have the courtesy (to call us)" before running the ad, Cao spokesman Devin Johnson told FoxNews.com. "That hurt the congressman. At least, he wanted that courtesy." Idiot.