Mitt Romney's campaign is intensifying calls for his Republican opponents to concede defeat before the GOP presidential race's next big election, Tuesday in Illinois.Romney extended his delegate lead Sunday in Puerto Rico by trouncing rival Rick Santorum.
1. The margins
Mitt Romney did what he was supposed to do in Arizona, winning by almost 20 points and pocketing all 29 delegates in the winner-take-all primary. That gives him a commanding lead over his nearest rival, Rick Santorum, for the GOP nomination, 145 to 82.