AMERICAN presidential politics never really takes a break these days, so the circling contenders and their gurus are already focused on 2016.

Republican presidential nominee Mitt Romney was desperately trying to steady a shaky campaign as US President Barack Obama, enjoying a burst of momentum, headed to New York for a celebrity fundraiser with Beyoncé and Jay-Z, along with a star turn on David Letterman’s couch.

Republicans bestowed their presidential nomination on Mitt Romney, turning to the former Massachusetts governor and multi-millionaire businessman to drive Barack Obama from the White House and usher in a new era of small-government conservatism.

US presidential candidate Mitt Romney’s whining and flip-flopping is making him look like a wimp with something to prove, not a steady future leader of the Western world, writes Michael Tomasky

Rolling Stone’s Matt Taibbi celebrates the 40th anniversary of Hunter S Thompson’s classic account of the campaign trail for the US presidential election in 1972

Mitt Romney has clinched the Republican presidential nomination with a win in the Texas primary.

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.

Irish-Americans, like the rest of the US electorate, will be concerned with jobs and the economy, writes Gary Murphy

Barack Obama will headline his first re-election rallies next week.

With the Republican presidential nomination all but in hand, Mitt Romney is refocusing his efforts on challenging President Barack Obama, raising cash for what may be the most expensive presidential contests in American history.

Mitt Romney’s path to becoming Republican presidential candidate has cleared further with advisers to rival Newt Gingrich saying he will formally end his campaign next week.

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

With Mitt Romney now all but assured of winning the Republican nomination, he embarks on one of his critical quests of the campaign: finding a running mate who can help him defeat President Barack Obama.

Mitt Romney, freed of his last serious challenger for the Republican presidential nomination, has unleashed blistering attacks on Barack Obama, assuring a brutal tone for the coming election campaign.

Rick Santorum dropped out of the race for the US Republican presidential nomination, leaving the field clear for Mitt Romney as the party’s likely choice to challenge President Barack Obama.

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 faces a daunting to-do list as he transitions into the role of likely Republican presidential nominee.

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.

Mitt Romney’s campaign has made a practice of tearing down fellow Republicans in the race for the presidential nomination, but now he’s coming under heavy assault himself as president Barack Obama’s team revs up its campaign for the November election.

US Republican presidential candidate Mitt Romney focused entirely on Democratic President Barack Obama during a campaign trip ahead of the Wisconsin primary, and predicted a victory that could effectively seal the nomination for him next week.

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.

Rick Santorum won the Louisiana Republican presidential primary, beating front-runner Mitt Romney in the race to challenge President Barack Obama.

Fresh off a decisive victory in Illinois, Mitt Romney won critical establishment support from former Florida Governor Jeb Bush as he looks to unite the Republican Party behind his candidacy.

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.

Republican White House hopeful Rick Santorum was under pressure yesterday to explain why he applauded a ranting evangelical pastor in Louisiana who told non-Christians to get out of America.

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 has lambasted Mitt Romney, calling him a flawed candidate and asking for a one-on-one debate with the former Massachusetts governor.

Republican White House hopefuls have set their sights on President Barack Obama’s home state of Illinois in the hope of shaking up the plodding race to become their party’s standard-bearer.

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.

Mitt Romney is hoping for a breakout victory in primary votes in America’s conservative deep South, looking for a win in Alabama or Mississippi that would accelerate his campaign for the Republican nomination.

Republican candidates battled hard ahead of today’s key deep South votes as a poll said front-runner Mitt Romney would beat Democrat President Barack Obama if elections were held right now.

The leading Republican presidential hopefuls focused their campaigns on the Deep South, with polls showing a tight three-way contest in tomorrow’s pivotal primaries in Alabama and Mississippi.

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’s presidential campaign would like to be focusing its attacks on Democratic President Barack Obama around now.

Urging conservatives not to yield, Rick Santorum is telling supporters in Mississippi that they could make the Republican presidential contest a two-man race if they deliver him a victory next week.

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 moved a step closer to clinching the Republican presidential candidacy after his Super Tuesday victory in the key Ohio primary.