Two of the nation’s most-contested battleground states — Pennsylvania and Arizona — illustrate the difficulties each campaign faces in gaining a clear advantage in the final stretch of the 2024 race, with Kamala Harris maintaining a narrow lead in Pennsylvania but Donald J. Trump continuing to hold an advantage in Arizona, according to a new pair of New York Times/Philadelphia Inquirer/Siena College polls.

The polls, from two states separated by more than 2,000 miles, show the challenge confronting both campaigns as they try to make their closing pitches to a diverse set of voters who have, at times, competing priorities.

In both Arizona and Pennsylvania, Ms. Harris has consolidated support among Democrats since replacing President Biden as the party’s nominee. But Mr. Trump’s strength remains the economy, the issue primarily responsible for his political potency across Arizona and other battleground states this year.

In Pennsylvania, Ms. Harris’s polling lead has been steady, though the state remains tight. Her advantage, 50 percent to 47 percent, falls inside the margin of error. But this was the third Times/Siena survey in two months showing support for Ms. Harris from at least half of the state. (Her lead in the poll was four percentage points when calculated using unrounded figures.)