You don't make a risky pick like Paul Ryan if you think the fundamentals favor your candidate. You make a risky pick like Paul Ryan if you think the fundamentals don't favor your candidate. And, right now, the numbers don't look good for Romney: Obama leads in the Real Clear Politics average of polls by more than four percentage points -- his largest lead since April.
With Paul Ryan on the ticket, Mitt Romney's loss will be conservatism's loss, too. And if Romney wins, then Ryan will a footsoldier in the Romney White House, not an independent power center pushing for conservative policies.