Republican race: Mitt Romney close to victory but Rick Santorum fights on

Mitt Romney has taken a step closer to the Republican presidential nomination by winning primaries in Wisconsin, Maryland and Washington DC.

The wins extend Mr Romney’s already significant delegate lead over chief Republican rival Rick Santorum, who defied growing pressure to abandon his candidacy in the name of party unity.

Wisconsin was the main contest of the night, the only place where Mr Santorum mounted a significant effort ahead of the contests. Former House Speaker Newt Gingrich and Texas Congressman Ron Paul trailed far behind in the primary results.

After the victories Mr Romney shifted his focus to the election with a sharp attack on President Barack Obama.

Earlier the President attacked Mr Romney in the latest sign that he views the former Massachusetts governor as his November election opponent.

In his victory speech Mr Romney said Mr Obama was an “out-of-touch liberal” and blamed him for home foreclosures, government debt and fuel prices.

He claimed more Americans had lost their jobs under the Obama administration than under any other president since the Depression.

“These last few years have been difficult, made worse by mistakes and failures of leadership,” Mr Romney said.

“Four more years?” he asked sarcastically of the president as supporters cheered him in Milwaukee.

Analysts say the former Massachusetts governor is close to a tipping point where Mr Santorum would be unable to catch him in the race.

Mr Santorum only seriously competed in Wisconsin, an agricultural and manufacturing state that was the night’s biggest prize.

Mr Romney, who has cemented his lead over Mr Santorum through overwhelming spending on television advertising, will face a better organized, better financed Obama campaign backed by the power of the presidency. For Mr Romney, the end of the contested primary campaign could hardly come soon enough.

The President has gained in the polls in recent months, particularly among women, as Republicans vie among themselves for support from the party’s increasingly conservative base.

Mr Santorum has devoted more time to social issues – including birth control – than Mr Romney, who has generally stayed focused on economic issues.

Additionally, surveys indicate Americans are growing more optimistic about the overall state of the economy. Unemployment has fallen in recent months, but it is still at a relatively high 8.3 percent of the work force.