California Sen. Kamala Harris sent a signal to the old guard of Democratic politics that every era has its end.
At an Atlanta church service Sunday, the presidential candidate compared leadership to a relay race in which each generation must ask themselves, "What do we do during that period of time when we carry that baton?"
Then she added with a smile that for "the older leaders, it also becomes a question of let's also know when to pass the baton."
At 54 years old, Harris is one of the younger contenders for the White House in 2020. While former Vice President Joe Biden has not said whether he will run, both the 76-year-old and 77-year-old Bernie Sanders have previously run for the White House and fallen short.
Biden and Sanders are seen as strong contenders for the Democratic nomination, though other candidates and some voters have emphasized the need for a more youthful approach to try and beat President Donald Trump in the general election. Several other candidates in the race, including two governor, are also in their late sixties.
Other highlights of Sunday campaigning:
Democratic presidential candidate Kirsten Gillibrand assailed President Donald Trump as a coward who is "tearing apart the moral fabric of the vulnerable," as she officially started her campaign for president.
The senator spoke in New York Sunday, feet away from one of Trump's signature properties, the Trump International Hotel and Tower.
She said that instead of building walls as Trump wants to do along the U.S.-Mexico border, Americans build bridges, community and hope.
Gillibrand also called for full release of special counsel Robert Mueller's report in the Russia investigation. Attorney General William Barr released a summary Sunday afternoon, but Democrats want to see the full details.
Gillibrand is trying to position herself in the crowded field of Democrats seeking the party's nomination. While some hopefuls have shied away from mentioning Trump, Gillibrand has not hesitated to do so.
Sen. Elizabeth Warren said Sunday the National Rifle Association is holding "Congress hostage" when it comes to stemming gun violence.
The Massachusetts senator and Democratic presidential candidate tells a campaign rally that if seven children were dying from a mysterious virus, "we'd pull out all the stops till we figured out what was wrong." But in terms of gun violence, she said the NRA "keeps calling the shots in Washington."
Warren finished a two-day campaign trip to New Hampshire with an event at a middle school in Conway Sunday afternoon.
Warren focused much of her speech on her approach to economics, but paid special attention to unions Sunday. She said more power needs to be put back in the hands of workers.
Democratic presidential candidate Beto O'Rourke told voters in Las Vegas Sunday that President Donald Trump bears blame for the separation of families at the U.S.-Mexico border but responsibility lies with everyone in the country to fix the situation.
O'Rourke spoke Sunday to more than 200 people packed into and snaking around a taco shop on the city's north end. He said immigrant families are leaving their home countries and journeying on foot because they have no other choice.
The former Texas congressman said desperate families were broken up in the U.S. when they were at their most vulnerable and desperate moments, and what happened to them "is on every single one of us."
Associated Press writers Juana Summers and Michelle Price contributed to this report.