Most voters won't be listening to Ralph Nader and his third-party platform this season for one simple reason, says UC Davis political scientist Walter Stone.

The voters see a clear choice between the Democrats and Republicans and won't be as interested in electing Nader to change the country's direction, says Stone, who studies the dynamics of third parties in American politics.

"The Bush administration has followed a set of policies that clearly shows it as one of the most conservative administrations in history -- in some ways more conservative than the Reagan administration," Stone says.

"As a result the differences between the major parties are more apparent to most voters this year than they were in 2000 or 1992, leaving less room for a third-party candidate to get traction."

Even when voters think there's little difference in the two main parties, third parties wield power only when they field a nationally popular presidential candidate such as Perot or Nader, Stone points out.

Once Perot created his third party and articulated their concerns, the Republicans saw a possible voting bloc that could help their candidates win.

"But it came at a price because it meant expanding the platform to absorb the third-party concerns," Stone says.

The Republican takeover in Congress in 1994 was made possible when the Republican Party, under the leadership of Newt Gingrich, made an overt attempt to appeal to the Perot constituencies.

Using the Contract With America, Republicans embraced their concerns, especially the need for internal reforms within Congress and the federal government's deficit.