THERE ARE no “quick fixes” in election campaigns. Kamala Harris’s entry into the presidential election puts this conventional wisdom to the test. In two weeks as the Democratic Party’s presumptive nominee, the vice-president has broken fundraising records and enthused the Democratic base. Her rise to the nomination has been smooth, although Republican attacks on her have barely begun. Now, with enough polling to see the effect of her candidacy, The Economist has published an updated poll tracker. It shows Ms Harris leading her opponent, Donald Trump, by 47% to 46% in the national popular vote. This is the first lead for the likely Democratic candidate since October 2023, though such a small margin suggests that the race for the popular vote is in essence a tie.