Robert F Kennedy Jr’s poll ratings in the US presidential race have dropped sharply since Kamala Harris entered the fray last month.

The independent candidate, who was polling at 15 per cent earlier this year, is now supported by just 2 per cent of voters, according to a CBS News poll released on Sunday.

The front-runners are closely matched, with Ms Harris on 49 per cent and Donald Trump on 47 per cent.

Mr Kennedy’s waning popularity suggests the wave of enthusiasm for the vice-president, who became the Democratic candidate after Joe Biden stepped aside two weeks ago, has eaten into his support.

It may also suggest Mr Kennedy, who launched his long-shot presidential bid in April 2023, was appealing to a section of the electorate put off by the prospect of either another Trump or Biden presidency.

The 70-year-old independent candidate looked relatively young compared to the two older men. That is no longer the case against the 59-year-old Ms Harris.

A Wall Street Journal poll from July 26 that showed the vice-president taking a narrow national lead over Donald Trump put Mr Kennedy on 4 per cent. A New York Times/Siena poll the day before put his support slightly higher – at 6 per cent.

Some commentators have dismissed Ms Harris’s ascent as a “sugar high” that will wear off as the presidential election in November draws closer.

But it remains to be seen if Mr Kennedy can last that long, as his campaign loses momentum and he cancels several public events.

Funding has also become a problem despite repeated cash infusions from Nicole Shanahan, Mr Kennedy’s lawyer running-mate. Ms Shanahan is the ex-wife of Sergey Brin, Google’s billionaire co-founder.