A new poll shows President Clinton has reopened a 21-point lead over Republican challenger Bob Dole, USA Today reported Tuesday.

A USA Today/CNN/Gallup poll taken over the weekend showed that Dole's boost from last month's Republican convention, which had narrowed Clinton's lead to nine percentage points, had evaporated. Clinton got a similar surge from his nomination at the Democratic Party convention last week in Chicago.If the November election were held today, 55 percent of those polled would vote for Clinton, 34 percent for Dole and 6 percent for third-party candidate Ross Perot, the poll showed. Clinton had a 22-point lead in a poll concluded on Aug. 7.

No presidential candidate who has trailed after the Labor Day holiday has come back to win except for incumbent Democrat Harry Truman in 1948. The poll showed 60 percent of voters approved of the way Clinton was doing his job, his highest rating ever. Clinton led Dole on the handling of all key issues, from crime to taxes.

The survey also indicated Republican control of Congress could be in serious danger. Asked how they plan to vote in the congressional elections, voters favor Democrats by 10 points, their largest advantage all year.

The poll involved 1,009 registered voters and was conducted from Aug. 30 to Sept. 1. The margin of error was plus or minus 3 percentage points.