While there is little question that Mitt Romney will be the Republican presidential nominee, Smart Politics notes that Romney continues to wrap up the nomination in a historically weak fashion.
"Over
the last 40 years there have been nearly 80 contests in which the
presumptive Republican nominees played out the string after their last
credible challenger exited the race. In every one of these contests, the
GOP frontrunner won at least 60% of the vote, even when ex- and
long-shot candidates remained on the ballot. But on Tuesday, Romney won
only 56% of the vote in Delaware and 58% in Pennsylvania,
home to Rick Santorum who dropped out on April 10th."