Presidential hopeful Senator Barack Obama won primaries in Virginia, Maryland and Washington DC yesterday, as his rival for the Democratic nomination faced serious questions about her campaign.

Senator Hillary Clinton flew to Texas, a key state, as analysts pored over data that suggests her support among women, Hispanic and older voters may be weakening in the face of Obama’s string of wins.

“We’re going to sweep across Texas in the next three weeks,” the former First Lady said.

“I’m tested, I’m ready, let’s make it happen.”

She made no mention of her sting of defeats.

Her deputy campaign manager is reported to have resigned, just

days after her campaign manager departed.

Senator Obama has won eight primaries and caucuses contests in four days and is expected to pick up Hawaii and Wisconsin next week.

It is not just the number of wins but the margin of victory that is causing concern for Hillary Clinton.

In Washington DC Senator Obama took 75% of the vote, in Virginia 64%.

AP exit polls found that two thirds of male voters and 60% of female voters backed him yesterday.

Senator Obama now has 1,223 pledged delegates at the nominating Democratic convention at the end of the summer to 1,198 for Senator Clinton.

To win the nomination a candidate must have the support of 2,025 delegates.