A resurgent Rick Santorum won Tuesday’s Republican presidential caucuses in Minnesota and Colorado, a triumph that raised fresh questions about front-runner Mitt Romney’s ability to appeal to the conservative core of the party’s political base.
Mr Santorum, a former Pennsylvania senator also won a non-binding Missouri primary that was worth bragging rights but no delegates to the party’s national convention.
Mr Romney, the former Massachusetts governor, prevailed in both Minnesota and Colorado in 2008, the first time he ran for the nomination, but the Republican Party has become more conservative in both states since then.
The victories for Mr Santorum, a fierce and vocal opponent of abortion and gay rights, exposed Mr Romney’s long-time struggles to convince cultural conservatives that he is now in line with their beliefs despite his previous support of gay and abortion rights.
Sensing likely defeat, the former Massachusetts governor’s team had worked to lower expectations in the three states and the candidate himself had started emphasising his positions on social issues in the days since he won Saturday’s Nevada caucuses.
But Mr Santorum remains a long shot for the nomination because Mr Romney has an overwhelming advantage in funds, organisational strength and party support.