US President Joe Biden pulled even with his Republican challenger Donald Trump this week in the race to win the November election, a sign the contest remains close even after a widely panned debate performance by the Democrat, according to a new Reuters/Ipsos poll. Biden and Trump each had 40% support among registered voters in the two-day poll that concluded on Tuesday. A prior Reuters/Ipsos poll conducted June 11-12 showed Trump with a marginal 2 percentage point lead, 41% to 39%. The two faced off in a televised debate last Thursday, where Biden stammered throughout and failed to challenge Trump's attacks. The new Reuters/Ipsos poll also showed that, following the debate, about one-in-three Democrats think Biden should drop out of the race, something he has pledged not to do. The poll, which gathered responses online and nationwide from 1,070 US adults, had a 3.5 percentage point margin of error for registered voters, many of whom remain on the fence with about four months left before the Nov. 5 election. One in five registered voters said that they weren't sure for whom to vote, that they would pick a different candidate or that they would not vote at all. The latest poll did not include a question on support for independent candidate Robert Kennedy Jr. The June poll found that 10% of registered voters would back him if he appeared on the ballot. While nationwide surveys give important signals on American support for political candidates, just a handful of competitive states typically tilt the balance in the US Electoral College, which ultimately decides who wins a presidential election. Both candidates carry significant liabilities. For Biden, these include concerns about his age - 81 - that were magnified by his debate performance. The latest Reuters/Ipsos poll found that 83% of Democrats and 97% of Republicans agreed with a statement that in the debate, "Biden stumbled and appeared to show his age." Only 58% of Democrats and 11% of Republicans had the same assessment of Trump's debate performance. Trump, 78, in May became the first US president to be convicted of a crime, whether in office or after leaving the White House. He is scheduled to be sentenced in September and faces potential prison time after a jury found him guilty of 34 charges stemming from a hush money payment to an adult film actress before the 2016 presidential election.