The American public initially supports Medicare (search) legislation providing help with prescription drugs (search), but that support fades when presented with criticism of the bill signed into law this year, a poll released Saturday suggests.

Asked whether they support "a Medicare bill which among other things provides prescription drug coverage and allows private companies to provide some services," almost two-thirds, 63 percent, said yes, according to the poll by the National Annenberg Election Survey (search).

When those polled were presented with opponents' arguments that the bill won't help seniors that much and cutting costs will eventually destroy Medicare, support faded. After hearings those arguments, only one in five of the total sample, 21 percent, supported it and another two in five said they were unsure.

Opposition to the bill weakened when opponents were given the additional argument that cutting costs is essential for Medicare to survive.

The poll found that almost half in the sample were unsure about the Medicare bill once questions were raised on either side.

During a campaign year, both sides are certain to vigorously debate the measure.

The poll of 1,615 adults was taken from Dec. 8-23 and has a margin of sampling error of plus or minus 2 percentage points.