David Goldman, Associated Press
Sen. John McCain, R-Ariz., left, and South Carolina Gov. Nikki Haley, center, attend an event in support of Republican presidential candidate former Massachusetts Gov. Mitt Romney, right, Thursday, Jan. 5, 2012, in Charleston, S.C.

WASHINGTON — CONWAY, S.C. -- Former Massachusetts Gov. Mitt Romney is keeping his focus on President Barack Obama as he works South Carolina, leaving the Republican intraparty attacks to his new public ally, Sen. John McCain.

Romney continued his criticism of Obama's handling of the economy, even as unemployment dropped in December by its largest percentage nationally in four years. Romney also criticized Obama's plan to shrink the military and focus more on Asia. Romney called it "inexcusable" and said the policy must be reversed.

McCain won the South Carolina primary four years ago. He's been a crusader against spending, and on Friday the Arizonan criticized Rick Santorum, his former Senate colleague, for supporting earmarks. McCain told an audience of more than 300 in Conway, S.C.: "Earmarks are the gateway to corruption."