Republicans are retreating from a handful of battleground U.S. House races, while Democrats are racing to raise money to boost candidates who seemed like long shots earlier this year.

The strategy in the final three weeks of midterm campaigns points to an increasingly defensive posture by Republicans, who have already trimmed their expectations in U.S. Senate races, and new aggression from Democrats, who are trying to capitalize on President Donald Trump's weak approval ratings.

Kamala Harris is building out her final fall campaign blitz on behalf of other Democrats, completing a midterm schedule that by Election Day will have taken her to multiple early presidential primary states on Democrats' 2028 calendar as the former vice president mulls whether to seek the White House again.