New Mexico's Gov. Bill Richardson, pictured here on May 29, 2008, has some thoughts on what a potential VP should have on his resume. (Associated Press) By Keith B. Richburg NEW YORK -- One of the rules of being picked as a vice-presidential running mate is to never, ever openly express an interest in the job. And New Mexico Gov. Bill Richardson knows the rule well, avoiding a direct answer when asked here, at a Council on Foreign Relations luncheon, if he'd like to be on the Democratic ticket with Sen. Barack Obama. "This is a decision that Sen. Obama needs to make," Richardson said. "And you don't need to make it now. Otherwise, what are we going to do at the Democratic convention in August?" At another point, Richardson said he would be "honored" to be asked, but said he also liked being a governor. But the rule about ...