Biden vs Trump would be a close rematch, with RFK Jr a threat to Biden -Reuters/Ipsos poll

By Jason Lange and James Oliphant

WASHINGTON (Reuters) -A looming election rematch next year between U.S. President Joe Biden and his predecessor Donald Trump would be closely fought, a new Reuters/Ipsos poll found, with both candidates saddled with profound vulnerabilities that could cost them the White House.

Biden, an 81-year-old Democrat, continues to be plagued by voters' doubts about the strength of the economy, as well as concerns about the security of the U.S.-Mexico border and worries about crime.

Republican former President Trump, 77, faces his own worries, including four criminal trials on a bevy of charges related to his attempts to overturn the 2020 presidential election and his handling of classified documents. A conviction prior to the Nov. 5, 2024, election could cost him significant support, the poll found.

The poll showed Trump with a marginal 2-point lead in a head-to-head matchup, 38% to 36%, with 26% of respondents saying they weren't sure or might vote for someone else.

The poll, conducted online Dec. 5-11, surveyed 4,411 U.S. adults nationwide and had a credibility interval, a measure of precision, of about 2 percentage points.

Trump is the frontrunner for the Republican nomination by a wide margin, the poll showed.

The state-by-state Electoral College system used to pick presidents, and deep-seated partisan divides, mean that voters in just a handful of states will play a decisive role in the election's outcome.

In the seven states where the election was closest in 2020 -- Wisconsin, Pennsylvania, Arizona, Georgia, Nevada, North Carolina and Michigan -- Biden had a 4-point lead among Americans who said they were sure to vote.

Overall, the poll showed deep apathy among many voters at a potential Biden-Trump rematch. About six in 10 respondents said they were not satisfied with America's two-party system and want a third choice.

RFK JR FACTOR

They may have one, in the form of anti-vaccine activist Robert F. Kennedy Jr., who has launched an independent bid. The poll showed that Kennedy, part of the storied political family, could draw more support from Biden than Trump.

Trump's lead widened to a 5-point advantage nationally when respondents were given an option to vote for Kennedy.

Some 16% of respondents picked Kennedy when given the option, while Trump had 36% support, compared to 31% for Biden. Trump also led Biden by five points in the seven swing states when Kennedy was as option.

Kennedy, whose uncle John F. Kennedy served as president and whose father, Robert, was a senator and attorney general, faces a challenge to amass enough signatures to get on the ballot on all 50 states. Last week, a super PAC fundraising committee backing Kennedy's bid said it would spend up to $15 million to get Kennedy on the ballot in 10 states as a starting measure.

Third-party candidates have affected the outcome of U.S. elections even without winning. In 1992, a strong showing by Ross Perot helped put Democrats Bill Clinton in the White House and in 2000, some Democrats blamed Ralph Nader's bid for contributing to Al Gore's loss to Republican George W Bush.

Biden would be the oldest president ever elected to a second term if he won in 2024, and other polls have shown that some voters are concerned about his advanced age.

But his candidacy likely will be buttressed by the public's continued support of abortion rights, as well as his advocacy for gun control, climate-change measures and higher taxes on the ultra-rich, the new Reuters/Ipsos poll showed.

The survey also highlighted the significant risks to Trump's campaign as he faces a series of criminal trials next year. Some 31% of Republican respondents said they would not vote for Trump if he was convicted of a felony crime by a jury. He has denied any criminal wrongdoing.

Some 45% of respondents said Trump was the better candidate for handling the economy, compared to 33% who picked Biden.

Biden, however, had a similar advantage on the issue of abortion, with 44% of respondents saying he was the better candidate for abortion access, compared to 29% who picked Trump.

Some of Trump's strength also appeared tied to concerns by some voters about crime and immigration. Asked which candidate was better on the issues, 42% picked Trump on crime compared to 32% who selected Biden.

Fifty-four percent of respondents agreed with a statement that "immigration is making life harder for native-born Americans," with a similar share saying Trump was the better candidate for the issue.

(Reporting by Jason Lange and James Oliphant; Editing by Scott Malone, Rosalba O'Brien and Mark Porter)