Rick Santorum revives presidential hopes © Reuters/Sarah Conard Former US senator Rick Santorum revived his presidential hopes on Tuesday with a surprise sweep of the three nominating contests in Colorado, Minnesota and Missouri. In a blow to Mitt Romney, Santorum trounced the front-runner by 30 percentage points in Missouri, which despite being a non-binding primary, has symbolic value as a measure of support in a big Midwestern state. After big wins in Nevada and Florida in the previous week, Romney had done little campaigning in Minnesota and Missouri and had been expected to win easily in Colorado. Even though he still holds strong advantages in financing and organisation, his campaign will now have to refocus to fight back the challenge from the surging conservative Santorum. With eight contests to date in the Republican race - including the three on Tuesday - Santorum has now won in four states, Romney in three and former House of Representatives speaker Newt Gingrich in one.