A double-digit increase in popularity, rising Democratic enthusiasm and an early edge for representing “change” have vaulted Vice President Kamala Harris forward and reshuffled the 2024 presidential contest, according to a new national NBC News poll. With just over six weeks until Election Day, the poll finds Harris with a 5-point lead over former President Donald Trump among registered voters, 49% to 44%. While that result is within the margin of error, it’s a clear shift from July’s poll, when Trump was ahead by 2 points before President Joe Biden’s exit. But the transformation in the presidential contest goes well...