Joe Lieberman (search) had the most support from Democratic voters in a national poll released Thursday, followed closely by Dick Gephardt, John Kerry and Howard Dean. But if Sen. Hillary Rodham Clinton of New York is added to the field, she dominates, taking 48 percent to 11 percent for Lieberman, with others in single digits.

Lieberman, a Connecticut senator, was at 21 percent and Gephardt, a Missouri representative, was at 16 percent - just within the error margin of plus or minus 5 percentage points in the Quinnipiac University (search) poll.

Kerry, a Massachusetts senator, was at 13 percent and Dean, a former governor of Vermont was at 10 percent. Other candidates in the nine-member field were at 6 percent or lower. More than a fifth, 21 percent, were undecided.

In several recent national polls, Lieberman, Kerry and Gephardt were grouped very close together at the top. Lieberman led early national polls, at least partially because of his higher name recognition.

When President Bush (search) is matched head-to-head against top Democrats in the poll, he leads by margins ranging from 7 points over Clinton to 16 points over Dean. Bush's lead against Kerry, Gephardt and Lieberman was about 10 points.

The poll of 1,055 registered voters was taken July 17-22, including 372 Democrats. The error margin for the overall sample was plus or minus 3 percentage points.