Mitt Romney is poised to clinch the Republican presidential nomination after today’s Texas primary, a largely uncontested election which will formalise the former Massachusetts governor’s status as President Barack Obama’s general election challenger.

Mitt Romney’s foreign policy vacillation typifies how the Republican Party has struggled to keep up with developments, says Leslie H Gelb

Mitt Romney has laid claim to a fiercely-contested Republican presidential nomination by sweeping five primary contests.

Bowing to the inevitable, Rick Santorum quit the US presidential campaign last night, clearing the way for Mitt Romney to claim the Republican nomination.

Bowing to the inevitable, Rick Santorum quit the presidential campaign today, clearing the way for Mitt Romney to claim the Republican nomination.

Mitt Romney is turning away from his primary opponents and towards Democratic President Barack Obama after sweeping three more Republican contests.

Republican front-runner Mitt Romney and president Barack Obama are trading blows as though the former Massachusetts governor has already locked up his party's nomination.

Mitt Romney tightened his grip on the Republican presidential nomination, sweeping three primaries in Wisconsin, Maryland and Washington, DC, and urged his party to shift focus to the general election showdown with President Barack Obama.

Mitt Romney charged toward the Republican US presidential nomination last night, aiming for big victories in Wisconsin and two other contests that would increase the pressure on rival Rick Santorum to drop out of the race.

Mitt Romney looked with confidence toward a victory in three more primary elections today and has increasingly turned his rhetorical fire on president Barack Obama, saying he relies on Europe for political inspiration.

Rick Santorum attacked rival Mitt Romney calling him “the worst Republican in the country to put up against Barack Obama” even as it appears the former Massachusetts governor is on course to clinch the Republican party’s nomination.

Mitt Romney easily won the Republican presidential primary in Illinois, increasing his already-formidable lead over chief rival Rick Santorum with another victory in a key industrial state.

The heartland state of Illinois is the next test today in the Republican party’s presidential nominating contest and one that would seem tailor-made for moderate front-runner Mitt Romney.

Rick Santorum won crucial primaries in Alabama and Mississippi in the race for the Republican presidential nomination, dealing a devastating blow to Newt Gingrich and securing his position as the chief conservative alternative to front-runner Mitt Romney.

Newt Gingrich says Mitt Romney is the weakest government opposition party front-runner since 1920, but his sizeable campaign fund allows him to run well in races where his rivals don’t have the resources to campaign.

Rick Santorum overwhelmingly won the Kansas presidential caucuses, hoping to blunt front-runner Mitt Romney’s momentum in the grinding campaign for the nomination to oppose President Barack Obama in the November election.

Rick Santorum has picked up a solid caucus win in Kansas today as he rushes to block Mitt Romney's Republican presidential nomination march.

Mitt Romney reached out to conservatives suspicious of him and sought to assert himself as the inevitable Republican US presidential nominee, despite failing to deliver a knockout blow to his rivals in the biggest round of nominating contests.

Mitt Romney has added the Alaska caucuses after he squeezed out a win in the pivotal Ohio primary and captured four other states in the race for the Republican presidential nomination.

Republican presidential hopefuls are preparing for the crucial Super Tuesday primary and caucus votes in 10 US states.

Today is the single biggest day of the Republican presidential campaign — or, as Newt Gingrich’s political action committee put it last night, the event that could represent “life or death to America as we know and love it”.

A Washington state victory in hand, Mitt Romney is looking ahead to tomorrow’s 10-state bonanza that features contests from Alaska to Ohio to Massachusetts, millions in campaign spending and the largest single day of voting yet in the Republicans’ topsy-turvy primary race.

Mitt Romney scored a hard-fought triumph in his native state of Michigan and powered to victory in Arizona today, dealing a blow to his chief rival and gaining precious momentum in the turbulent Republican presidential race.

Regardless of the outcome of Republican presidential primaries in Michigan and Arizona today, Mitt Romney and Rick Santorum appear set for a showdown next week in Ohio.

Mitt Romney is fighting his way back into the driver’s seat in the Republican presidential race, putting in a strong debate performance in Arizona and gaining in polls against conservative rival Rick Santorum.

Mitt Romney and Rick Santorum, who has emerged as Mr Romney’s leading challenger in the Republican presidential race, clashed over the US federal government’s power in a high-stakes debate that might have been the last in the roller-coaster campaign to challenge President Barack Obama.

On Feb 6 it all seemed so clear. Mitt Romney had won landslides in Florida and Nevada and looked set to soon lock up the Republican presidential nomination to take on Barack Obama in November.

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.

Mitt Romney eked out a narrow win in Maine’s Republican caucuses, state party officials announced, providing his campaign for the party’s presidential nomination a much-needed boost after three straight losses earlier this week.

Republican presidential contender Rick Santorum claimed the momentum a day after his shocking sweep of nominating contests in Colorado, Minnesota and Missouri that dealt a blow to front-runner Mitt Romney.

Republican frontrunner Mitt Romney cruised to an easy victory in Nevada on Saturday, crushing his three remaining rivals and taking firm command of the party’s volatile presidential nominating race.

As more Republicans back him, Mitt Romney seems increasingly likely to be the party’s presidential nominee,writes Beth Fouhy

Republican presidential front-runner Mitt Romney cruised to victory in the Nevada caucuses today, notching a second straight triumph over a field of rivals suddenly struggling to keep pace.

Mitt Romney has won the Florida Republican presidential primary, early results showed today.

Anticipating victory in Florida’s game-changing Republican presidential primary last night, Mitt Romney looked ahead while his struggling rival Newt Gingrich vowed to fight on.

Mitt Romney is pushing for a big win over Newt Gingrich in tonight's Florida primary in a bid to re-establish himself as the front-runner in the race to pick a Republican challenger to President Barack Obama.

Mitt Romney said yesterday he has overcome his South Carolina setback and returned to the Republican primary forefront by aggressively returning Newt Gingrich’s fire and by presenting himself as a Washington outsider.

Newt Gingrich cast Mitt Romney as the most anti-immigrant candidate of the four contenders for the Republican presidential nomination in a heated campaign debate in Hispanic-heavy Florida.

Republican presidential contenders Mitt Romney and Newt Gingrich clashed repeatedly in heated, personal terms in the first campaign debate since South Carolina’s primary scrambled the race to pick a challenger to President Barack Obama.

Cash is pouring into the Newt Gingrich campaign for the Republican presidential nomination after the stunning surge and upset victory over Mitt Romney.

After a bruising clash in South Carolina, Republican presidential frontrunners Mitt Romney and Newt Gingrich took their battle to a bigger stage when the campaign moved to Florida yesterday.

Newt Gingrich stormed to a shock victory over Mitt Romney in the South Carolina primary today, scrambling the race to choose a Republican challenger to President Barack Obama.

Front-runner Mitt Romney and his Republican presidential pursuers enter the final full day of campaigning today in a South Carolina primary contest significantly changed from just 24 hours earlier.

The race for the Republican presidential nomination took several twists and turns as Rick Perry dropped out, Newt Gingrich faced stunning allegations from his ex-wife and Mitt Romney struggled to maintain a shaky front-runner's standing.