PENNSYLVANIA, OHIO and MICHIGAN — U.S. Rep. Ro Khanna was riding shotgun in a black Chevrolet Suburban hurtling down an Ohio highway. His mind was on the economy . "I do think I have the right economic vision for this country," Khanna, D-Calif., told CNBC, taking a break from answering one of the hundreds of text messages he receives each day. "The question is just whether I will get behind someone who can help adopt it, or whether I'll do it myself." The Silicon Valley representative had just