A growing trend in US elections is for a major party and its supporters to help a third party with the idea of taking votes that would otherwise be likely to go to the other major party’s candidates. This is the classic “divide and conquer” tactic. The idea is that if a third political party normally pulls far more voters from one major party than the other, the other major party can benefit by the third party doing well in the election. Currently in the US, the Green Party is viewed as pulling more from the Democratic Party than the Republican Party, and the Libertarian Party is viewed as taking more votes from the Republican Party than the Democratic Party.

Some third party advocates object to the notion that third parties “take votes away” from major parties, on the grounds that the major parties were never entitled to anyone’s vote to begin with. (See the discussion below, concerning “wasted” votes.)
In 1992, some political observers attributed the “success” of Ross Perot and his Reform Party for Democratic presidential candidate Bill Clinton’s defeat of incumbent Republican President George Herbert Walker Bush.

In 2000, the victory of Republican presidential candidate George W. Bush over incumbent Democratic Vice President Al Gore for the US Presidency was widely attributed to the “success” of Ralph Nader, running on the Green Party’s ticket.

In 2004, both parties showed strategic interest in Ralph Nader’s presidential campaign. Concerned that Nader might “spoil” the election for their candidate John Kerry (by attracting votes that would otherwise go to Kerry), the Democratic Party attempted to deny Nader ballot access in many states. The effort was largely successful. Even where the party failed to keep Nader off the ballot, the Nader campaign had to devote resources to ensuring ballot access. It was also reported that the Republican party assisted Nader’s efforts to get on the ballot.

Nader’s 2004 run was as an independent candidate; he generally emphasized his independence from any political party. He did, however, accept the nomination of the Reform Party in several states to gain ballot access. In other states, where the laws made forming a new party easier than qualifying as an independent candidate, Nader’s campaign revived the Populist Party in order to assure ballot access.