A conflict over ballot stacking is rocking the Alaskan Senate race between Republican Dan S. Sullivan and Democrat Mary Peltola. A retired teacher named Dan J. Sullivan also entered the race, causing confusion. Republicans say this tactic could cost the incumbent votes, though the campaign denied any involvement in the matter.

As a conflict over candidates roils the Alaskan Senate race, here's a look back at the political practice over the years.

Stacking a ballot is when a little-known candidate runs for election to divert votes from a more prominent opponent. It is widely considered a legal, if unsavory, tactic.

And it is rocking Alaskan politics this week.

The state's race for U.S. Senate is a tight contest between the Republican incumbent, Dan S. Sullivan, and the Democratic nominee, Mary Peltola. But also on the ballot is a retired schoolteacher named Dan J. Sullivan, from Petersburg, Alaska, who entered the race in the spring. Republicans say confusion over the Sullivans could cost the incumbent votes.

The New York Times found that operatives aligned with Ms. Peltola spent months recruiting candidates to siphon votes from her Republican competition. She and her campaign have denied any involvement with the lesser known Mr. Sullivan. That candidate also has denied any wrongdoing and said he was running because he was dissatisfied with Senator Sullivan.

The Trump administration has filed a lawsuit seeking to block certification of the election if the incumbent senator loses by a narrow margin, and Gov. Mike Dunleavy, a Republican, has called for an investigation.

Ballot stacking is hardly unheard of in American politics -- up and down ballots, across party lines. Here are a few examples.

Rick and Ricky

Rick Perry ran for governor of Texas in 2022, but do not confuse him with the former Texas governor and U.S. energy secretary by the same name.