Barack Obama, responding to a week of taunts from John McCain’s campaign, said Tuesday that his Republican detractors “take pride in being ignorant” and that it’s time to get serious. The Illinois senator was responding in part to criticism from Republicans who mocked him for suggesting last week that Americans could save on energy costs and gas by properly inflating their tires. McCain surrogates passed out tire gauges that say “Obama’s Energy Plan,” and McCain said last week the “only thing” Obama has proposed with regard to energy is to inflate tires. “This is the kind of thing they do....