Las Vegas ? Choosing “none of the above,” the default option on quizzes, is looming as a potential factor in the dead-heat Nevada Senate race for voters who don’t like either Democrat Harry Reid or Republican Sharron Angle.

Voters in the Silver State have nine choices on the ballot next week — eight are candidates, including Reid and Angle.

The number of voters who choose “None of these candidates” is expected to be small, but in a close race those who decide to boycott the ballot could make the difference.

Reid knows the risk: A dozen years ago he pulled off a 428-vote re-election victory over then-Republican Rep. John Ensign, while “none” received 8,125 votes, far more than his winning margin.

“A very small part of the electorate is lingering out there because they don’t like either choice,” said Republican consultant Ryan Erwin. But “every vote that goes for someone other than Sharron Angle is a vote for Harry Reid.”

The choice that is no choice has been on statewide Nevada ballots since 1976, added as a way to entice greater turnout by providing a protest vote. This year, it’s clearly a lure for voters fed up with everything — Washington, the sour economy and a corrosive campaign between two candidates prone to cringe-inducing gaffes.

The campaigns are making calculations about how it will play into the tally on Nov. 2, but there is some dispute over which candidate suffers more if a voter chooses to stiff-arm the field. Recent polls have shown the choice is favored by a small slice of voters, 2 percent to 4 percent.

In the June Democratic primary, nearly 11 percent of voters chose “none” over Reid, reflecting unrest within his own party. It’s not clear how many of those 12,335 Democrats might want to punish Reid again next week. In the GOP primary, “none” fared better than seven of the 11 candidates, pulling 3,090 votes, or 1.8 percent.