Republican officials have called for an investigation into an alleged ballot-stacking scheme in Alaska’s competitive Senate race by Democrat Mary Peltola’s campaign.

For months, Donald Trump and others accused Peltola and Democrats of recruiting candidates with the same name as her Republican opponent, Dan Sullivan, to purposefully confuse voters when they cast their ballots in November’s midterms.

Though Peltola’s campaign denied encouraging or soliciting a man named Dan J Sullivan to run, a recent New York Times report indicated Peltola’s campaign did recruit him.

Related: Democrat Mary Peltola’s campaign reportedly recruited second Dan Sullivan in Alaska Senate race

While ballot-stacking is not illegal itself, the US president and justice department have filed a lawsuit pre-emptively to block the certification of the Senate election results if the incumbent senator loses.

Here’s what to know about the situation and ballot-stacking.

What’s happened in the Alaska Senate race?

A man named Dan J Sullivan entered the Alaska Senate race as a Republican in May, challenging incumbent Republican Dan S Sullivan and Democrat Mary Peltola.

Dan J Sullivan, a retired schoolteacher and former US Forest Service employee, had no prior political experience. Republicans, including Dan S Sullivan, accused Democrats of planting Dan J Sullivan in the race to deliberately confuse voters.

Dan J Sullivan told the New York Times that he had no intention of trying to trick voters; rather, he was giving conservative Alaska voters another candidate. Peltola’s campaign also denied encouraging or soliciting Dan J Sullivan to run in the election to the Anchorage Daily News in May.

What has been reported?

On Wednesday, the New York Times reported that Peltola’s campaign engaged in an effort to recruit Dan J Sullivan, and other potential candidates with the name Dan Sullivan, to run against Dan S Sullivan.

The information came to light in interviews with at least a dozen people who participated in or were told of the plan, including Peltola’s former campaign manager and longtime aide, Elisa Rios.

Text messages and documents revealed Peltola’s campaign staff worked with senior aides at the Democratic Senatorial Campaign Committee (DSCC) to find “spoiler” candidates, including Dan J Sullivan, to run in the hopes of helping Peltola’s campaign.

What is ballot stacking?

Ballot stacking is a political tactic used in elections to draw votes away from an opponent by “stacking” the ballot with other candidates.

A political party, campaign or outside group may recruit additional candidates to run in an election. Sometimes the candidate may have a similar name to another opponent or appeal to a similar base of voters.

Ballot stacking is common and used by both Republicans and Democrats, the New York Times noted.

Is ballot stacking illegal?

Ballot stacking is not illegal and common in US politics.

Despite this, Todd Blanche, the US attorney general, told Fox News the situation amounted to “cheating” and “fraud” and that if those outcomes were true, it “certainly should be” considered illegal.

What would be considered illegal is if anyone lied under oath about the cooperation between Democrats and Dan J Sullivan, which constitutes perjury, the Election Law Blog noted. However, as of 29 October, there have been no accusations of such.

What has been the reaction?

Republicans have expressed outrage toward the alleged ballot-stacking scheme, calling for Peltola to be investigated and removed.

Trump accused Democrats of “voter fraud” and called for Peltola to be “removed from the Ballot and prosecuted”.

Alaska’s governor, Mike Dunleavy, said he would launch an investigation to determine if criminal charges or civil action were warranted.

Lisa Murkowski, a Republican Alaska senator, denounced ballot stacking and said the report revealed “a pattern of lies and coverups and a culture of deception”. However, Murkowski condemned the justice department for filing its lawsuit.