(The Hill) – Lawmakers in both parties are bracing themselves for a messy aftermath to Election Day as polls show the race between former President Trump and Vice President Harris is so close in several battleground states that it could take days to determine the winner.

Democratic senators say they fear Trump and his allies will seize on any initial uncertainty over the results to claim election fraud if Harris is projected the early winner.

Some lawmakers are already girding themselves for another battle on the Senate and House floors over certifying the election if Harris is declared the winner.

While Congress passed the Electoral Count Reform and Presidential Transition Improvement Act in 2022 to avoid a reprise of Jan. 6, 2021, when a pro-Trump mob marched on the Capitol, some Democrats worry that history may repeat itself.

“A reasonable person has to be concerned with the rhetoric that’s coming out of certain states and certainly out of the Trump campaign. Once again they’re setting the stage whereby any loss will be blamed on corruption at the ballot box, even when there’s no possible support for that allegation,” said Sen. John Hickenlooper (D-Colo.).

“I am concerned that there’s going to be chaos. They’re going to try to slow things down. If it looks like they’re losing, the Trump campaign will try every avenue possible,” he said.

Democrats have filed an ethics complaint in Georgia accusing members of the state election board of holding an illegal meeting and passing rules that exceed their authority.

The Center for Media and Democracy, a progressive nonprofit watchdog group, published a report this month claiming that more 230 officials in eight states — Arizona, Georgia, Michigan, Nevada, New Mexico, North Carolina, Pennsylvania and Wisconsin — have denied the legitimacy of the 2020 election or have spread claims of widespread voter fraud.

Democratic senators say they believe Trump is already laying the groundwork to contest the results of the election.

“I think that’s part of Trump’s plan already, and also to make the erroneous claim made in his last election … that he’s being robbed of the election, etc., which frankly will generate potential violence,” warned Sen. Jack Reed (D-R.I.).

Reed said he hopes Republican senators and House members would again refuse to block the certification of the election — if Harris is declared the winner — as many GOP lawmakers did on Jan. 6, 2021.

He also said officials may need to investigate allegations of political operators throwing out ballots without proper justification.

 “If there is systematic undercounting of ballots, that’s a crime and we have to look at it,” Reed said.

Most Senate Republicans voted to reject challenges to slates of electors from Arizona and Pennsylvania in 2020, but Sen. Mitt Romney (R-Utah), an outspoken Trump critic who is retiring, doesn’t know if GOP senators will be so quick to reject unsubstantiated claims of fraud this time around. 

“I don’t know,” he said. “Big question.”

More than 30 House lawmakers, including a handful of Republicans, have signed a bipartisan commitment to uphold the 2024 election results.

Sen. John Cornyn (R-Texas), an ally of Senate GOP Leader Mitch McConnell (R-Ky.), said he hopes the courts can settle disputes over election results before Congress votes to certify the election results on Jan. 6, 2025.

“I assume that would be litigated in the various states, as they were previously. That’s really not a decision for us to make and of course there are some constitutional deadlines that have to be met to be prepared for an inauguration on Jan. 20,” he said. “Hopefully we’ll win by a landslide, and it won’t be close.”

Trump’s victory over Hillary Clinton in 2016 and President Biden’s victory over Trump in 2020 were decided by a few thousand votes in several states: Arizona, Georgia, Michigan, Pennsylvania and Wisconsin.

Some Republican senators are warning that the influx of immigrants lacking permanent legal status into the country during President Biden’s four years in office poses a threat to election integrity, though there are relatively few documented instances of noncitizens voting in elections, which is illegal.

“We got to make sure it’s done the right way, that why we wanted the SAVE Act,” said Sen. Tommy Tuberville (R-Ala.), one of Trump’s closest allies, referring to a bill that conservatives tried to attach to spending legislation that would require proof of citizenship for voter registration.

“Unfortunately, a lot of the states are giving out drivers’ licenses and identification to a lot of people that aren’t citizens of this country. I think that’s the biggest thing people are going to complain about … it’s the count of the illegals voting in this election,” he said. “It could decide an election.”

An average of 2 million people per year crossed the border illegally from 2021 to 2023.

Asked whether Republicans would vote to delay the certification of the election if Trump raises objections raised to slates of electors, as he did in 2020, Tuberville said: “Let’s see how it goes, that’s a big hypothetical.”

“Hopefully it doesn’t happen the way it did during COVID, because COVID opened a big can of worms,” the Alabama senator said, referring to controversial changes to election laws that made it easier to vote by absentee ballot in some states, such as Pennsylvania. 

Pennsylvania expanded absentee voting in 2019, before the start of the pandemic.

House Speaker Mike Johnson (R-La.), another Trump ally, warned earlier this month immigrants living in the country illegally could sway the election.

“We’re in an era of razor-thin election margins,” he said at a press conference promoting the SAVE Act. “If you have a few thousand illegals participate in an election in the wrong place, you can change the makeup of Congress, and you can affect the presidential election.”

Polls show Trump and Harris within the margin of error in several battlegrounds, including Pennsylvania, North Carolina, Georgia, Nevada, Michigan and Wisconsin.  

Arizona and Georgia will now require election workers to conduct hand counts at polling sites, which officials say could delay the reporting of results.

At the Sept. 10 presidential debate, Trump alleged without citing specific evidence that Democrats want new migrants to vote in the election.

“A lot of these illegal immigrants coming in,” Trump said, gesturing to Harris. “These people are trying to get them to vote. And that’s why they’re allowing them to come into our country.”

He pressed the unsubstantiated claim again on Sept. 18 when he posted on Truth Social that “Democrats are registering Illegal Voters by the TENS OF THOUSANDS, as we speak — They will be voting in the 2024 Presidential Election, and they shouldn’t be allowed to.”

Sen. Mike Lee (R-Utah), another Trump ally, argued on the social platform X this week that while immigrants lacking permanent legal status can’t legally vote in federal elections, “sometimes they do anyway, and existing law makes it far too easy for them to do so.”

He reposted an online report that Oregon’s department of motor vehicles mistakenly registered 1,200 noncitizens to vote.

A Democratic senator who requested anonymity said the potential for a drawn-out fight over the election results is possible.

“I think it’s really scary,” the senator said of the possibility of Republicans claiming the 2024 election was stolen.

This senator said there are likely more Republicans in Congress now than on Jan. 6, 2021, who would back efforts to overturn a result in the election that did not go their way.

“Look at who’s gotten elected since [2020,]” the source said of Trump’s growing influence over GOP lawmakers in Washington.