Vice President Kamala Harris opened up a marginal two-percentage-point lead over Republican Donald Trump after President Joe Biden ended his re-election campaign and passed the torch to her, a Reuters/Ipsos poll found.

The poll, conducted on Monday and today, followed both the Republican National Convention where Trump on Thursday formally accepted his party’s nomination and the Biden announcement on Sunday he was leaving the race and endorsing Harris.

Harris, whose campaign says she has secured the Democratic nomination, led Trump 44% to 42% in the national poll, a difference within the 3-percentage-point margin of error.

Harris and Trump were tied at 44% in a July 15-16 poll, and Trump led by one percentage point in a July 1-2 poll, both within the same margin of error.

While nationwide surveys give important signals of American support for political candidates, just a handful of competitive states typically tilt the balance in the U.S. Electoral College, which ultimately decides who wins a presidential election.

The most recent poll results underscored the rationale for Biden dropping out of the race and for Harris replacing him on the ticket.

Some 56% of registered voters agreed with a statement that Harris, 59, was “mentally sharp and able to deal with challenges,” compared to 49% who said the same of Trump, 78.

Only 22% of voters assessed Biden that way.

Biden, 81, ended his reelection effort after a debate with Trump in which he often stammered and failed to aggressively challenge attacks by Trump that included falsehoods.

Some 80% of Democratic voters said they viewed Biden favorably, compared to 91% who said the same of Harris. Three-quarters of Democratic voters said they agreed with a statement that the party and voters should get behind Harris now, with only a quarter saying multiple candidates should compete for the party’s nomination.

When voters in the survey were shown a hypothetical ballot that included independent presidential candidate Robert F. Kennedy Jr., Harris led Trump 42% to 38%, an advantage outside the margin of error. Kennedy, favored by 8% of voters in the poll, has yet to qualify for the ballot in many states ahead of the Nov. 5 election.

Harris campaigned in the critical battleground state of Wisconsin today. She won support from major party figures and attention has since turned to who she will pick as her running mate.

Many respondents in the Reuters/Ipsos poll said they knew nothing about the Democrats seen as potential picks to join Harris’ ticket.

About one in four registered voters said they had never heard of U.S. Transportation Secretary Pete Buttigieg, a former Democratic presidential candidate who had the highest favorability rating – 37% – of the potential Harris running mates in the poll.

One in three had not heard of California Governor Gavin Newsom, with about the same share saying they looked on him favorably. Half of registered voters in the poll had never heard of Arizona Senator Mark Kelly and two-thirds knew nothing of Kentucky Governor Andy Beshear.

The poll, which was conducted online, surveyed 1,241 U.S. adults nationwide, including 1,018 registered voters.