(Agencies)
Updated: 2008-03-04 07:43

WASHINGTON: Hillary Rodham Clinton struggled to salvage her faltering campaign going into crucial nomination showdowns today as front-runner Barack Obama set his sights on ending his rival's bid for the Democratic presidential nomination.

US Senator and Democratic presidential candidate Hillary Clinton is escorted onto the stage by former Congressman Jack Brooks (L) at a campaign rally at the airport hangar in Beaumont, Texas. [Agencies]

Four states vote, but the focus is on races in the big states of Texas and Ohio where the former first lady made a concerted bid yesterday for votes. She desperately needs wins in both to salvage her once-powerful bid to become the US' first female president and halt Obama's momentum following his streak of 11 consecutive wins since the Feb 5 "Super Tuesday" races.

Recent polls show Clinton retains a lead - albeit a narrowing one - in Ohio.

In Texas, her once formidable lead has all but vanished and the race is now seen as a dead heat. A total of 370 delegates are at stake in the four races, including Vermont and Rhode Island.

Neck-deep in a campaign marked by feuding and acrimony, Clinton sharpened her attacks on Obama, targeting his foreign policy and national security inexperience while appealing to voters in Ohio with a message of solutions for their economic woes.

Obama's aides said privately that they felt they had a good shot at a win in Texas, but were less certain about Ohio, where they braced for a possible loss. Polls show Clinton leading in Rhode Island, but Obama ahead in Vermont.

Obama, who is seeking to become the US' first black president, has spent the past couple of days fending off attacks by Clinton.

"What precise foreign-policy experience is she claiming that makes her qualified to answer that telephone call at 3 am?" Obama asked of the former first lady at a town-hall meeting in Westerville, Ohio.

It was a reference to dueling television ads over who would exercise superior judgment in responding to a national emergency in the middle of the night.

Obama highlighted his opposition to the Iraq war during his successful 2002 Senate campaign months before the US-led invasion.

He criticized Clinton for failing to read the classified National Intelligence Estimate on Iraq's weapons capabilities, a report available at the time of her October 2002 vote authorizing the Iraq war.

"She didn't give diplomacy a chance. And to this day, she won't even admit that her vote was a mistake - or even that it was a vote for war," Obama said. "When it came time to make the most important foreign policy decision of our generation - the decision to invade Iraq - Senator Clinton got it wrong."

On the Republican side, the party's presumptive nominee, Arizona Senator John McCain, held sizable leads over former Arkansas Governor Mike Huckabee in the polls and was expected to sweep all four contests today - with more than 250 delegates at stake.