One in five Americans think Vice President Dick Cheney is the worst vice president in U.S. history, a new poll has found.

23 percent of Americans told a CNN/Opinion Research poll that Cheney is the worst vice president, compared to past vice presidents.

Conversely, one percent of those surveyed said Cheney has been the best vice president in American history.

41 percent rated Cheney as a poor vice president, while 34 percent approved of his tenure as the nation's second-in-charge constitutional officer.

The poll, conducted December 19-21, has a three percent margin of error.