WASHINGTON, Oct 19: The Republican effort to make Islam an issue in the US presidential election cost them the support of an iconic Republican figure, former secretary of state Colin Powell, who on Sunday endorsed Senator Barack Obama.

As the former Bush administration secretary of state announced his endorsement for Mr Obama, the Democratic election campaign said they had raised a mammoth $150 million in September. This breaks all previous records for collection of election funds in a single month.

The campaign said that Mr Obama now had more than 3.1 million donors across the US who would play a key role in bringing the voters out for Mr Obama on Nov 4.

And as many as 67 per cent respondents during an opinion survey said Mr Powell’s endorsement would be equally helpful in convincing the voters to back Mr Obama.

Mr Powell served four US presidents: Ronald Reagan, George H.W. Bush, Bill Clinton and George W. Bush, three of them Republicans. For many years, Mr Powell was considered the most likely candidate to become the first African-American president.

This is one of Senator Obama’s most major endorsements — and the most prominent Republican supporter.

In an interview on Sunday on Fox News, Republican presidential candidate John McCain said he was not surprised by the announcement. “I’ve always admired and respected General Powell,” said Mr McCain. “We have a respectful disagreement.” Mr Powell, however, said the Republican Party’s narrow focus on irrelevant personal attacks instead of a serious approach to issues confronting the US made him support a Democrat.

The former secretary said he was “troubled” especially by false intimations that Senator Obama was a Muslim. Such tactics, he said, were insulting not only to Mr Obama but also to Muslims.

“The really right answer is, what if he is?” he said, praising the contributions of millions of Muslim citizens to American society. “I look at these kinds of approaches to the campaign, and they trouble me,” Mr Powell said.

“Over the last seven weeks, the approach of the Republican Party has become narrower and narrower,” said Mr Powell in an interview to NBC News.