Republicans have launched a campaign against Vice President Kamala Harris after she emerged as the frontrunner to replace Joe Biden – who could quit the presidential race within days according to a key ally. Harris has been a staunch defender of Biden and has pushed back on concerns about his age and deteriorating cognitive abilities. However, a recent CNN poll has shown that Harris would be more likely to win in key demographics, including ethnic minority voters and independents, if she became the Democrat candidate. Now, Republicans are seizing on the potential fallout and have taken aim aga…