Mitt Romney’s increasingly confident campaign is intensifying calls — publicly and privately — for his Republican opponents to concede defeat in the presidential nomination battle, even before Illinois voters have their say Tuesday in the campaign’s next big contest.

Romney extended his delegate lead Sunday in Puerto Rico, where he trounced rival Rick Santorum and scored all 20 of the Caribbean island’s delegates. Romney has collected more delegates than his opponents combined and is poised to win the delegate battle in Illinois, even if he loses the popular vote, thanks to missteps by Santorum’s shoestring operation.