30 Days Out, the Harris and Trump Campaigns Brace for ‘Trench Warfare’

As Vice President Kamala Harris and former President Donald J. Trump begin the final 30-day push for the White House, they are locked in a neck-and-neck race from the Rust Belt to the Sun Belt.

With polling averages showing all seven battleground states nearly tied, many Democrats believe their biggest advantage may be an extensive ground game operation that their party has spent more than a year building across the country. Mr. Trump’s campaign thinks that recent events — the escalating conflict in the Middle East and deadly hurricanes that have killed more than 200 people across the Southeast — will give them an edge in the final weeks.

In some ways, the two approaches mirror the final days of the 2016 race, when Hillary Clinton’s campaign boasted about a massive, data-driven field organization while Mr. Trump pressed a national message based on stoking anti-immigrant sentiment and improving the economy with a relatively meager staff and almost no field operation in the key states. Mr. Trump, of course, prevailed, helped by the F.B.I. director’s reopening of an inquiry into the Democratic nominee’s emails.

This time, Democrats have no such overconfidence. Although Mr. Trump and his party have lost or underperformed in every major election since then, many Democrats believe this year is one they could lose.