Kamala Harris capped her first month as the Democratic Party’s presidential candidate with a roughly 35-minute convention speech last night that embodied her aggressive efforts to win over swing voters.

It was a patriotic speech that was hawkish on foreign policy and border security. She described the United States as the greatest country in the world — a view many Americans hold but most Democratic voters do not — and she ended by saying that being an American was “the greatest privilege on earth.” She promised to confront China, Russia, Iran and Iran-backed terrorists and to make sure that the U.S. military remained the “most lethal fighting force in the world.”

She also offered a series of populist promises to help the middle class by reducing the cost of housing and health care — policies that many independents and some Republicans favor. And she spent little if any time on subjects that inspire passion among Democrats but are either secondary or off-putting to many swing voters, such as student debt forgiveness and President Biden’s climate agenda.

You can read more about Harris’s speech in this news story, as well as in this article on how she contrasted herself with Donald Trump.

In today’s newsletter, I want to explain why Harris’s move to the political center seems to be working, at least so far.

Harris has surged in the polls, erasing Biden’s deficit and taking a small lead over Trump, for two main reasons. First, she has won over some swing voters, including independents, working-class Midwesterners and even a fraction of 2020 Trump voters. Second, she has done so at no apparent cost: In addition to attracting swing voters, she has built a bigger lead than Biden had among the Democratic base, such as young voters, college graduates and city residents.