Santorum plans aggressive strategy against Romney

PORTLAND, Maine — A day after Mitt Rom­ney regained some momen­tum in the Repub­li­can pres­i­den­tial con­test, his rival Rick San­to­rum went on the attack, call­ing the front-runner “des­per­ate”; while promis­ing to com­pete aggres­sively to win the state where Rom­ney grew up.