AMNA NAWAZ: Welcome to the "News Hour."

The 2024 campaign is in full swing, with Vice President Kamala Harris' running mate, Tim Walz, hitting the trail on his own for the first time.

GEOFF BENNETT: It comes a day after former President Donald Trump's two-hour livestream with Elon Musk on X, formerly Twitter.

But what was billed as a triumphant return to that social media platform was fraught with tech troubles.

Laura Barron-Lopez starts our coverage.

LAURA BARRON-LOPEZ: Minnesota Governor Tim Walz in Los Angeles, California, today, stop number one of a five-state dash that has the V.P.

pick flying solo for the first time.

GOV.

TIM WALZ (D-MN), Vice Presidential Candidate: We can't hope that we defeat Donald Trump.

We can't hope that we can collectively bargain.

We can't hope we protect Social Security.

We can't hope that we address climate change.

You don't hope to win.

You plan, prepare and work to win.

(CHEERING) (APPLAUSE) LAURA BARRON-LOPEZ: He addressed the American Federation of State, County and Municipal Employees at its annual convention, the largest trade union representing the public sector in the U.S., and it already endorsed the Harris/Walz ticket.

GOV.

TIM WALZ: We know exactly who built this country.

It was nurses, it was teachers, and it was state and local government employees that built this nation.

(CHEERING) (APPLAUSE) GOV.

TIM WALZ: People in this room built the middle class.

Thank you, AFSCME.

LAURA BARRON-LOPEZ: Walz will spend the coming days fund-raising across the country, a level of campaigning relatively new for the former teacher and coach.

Meanwhile, for Trump... DONALD TRUMP, Former President of the United States (R) and Current U.S. Presidential Candidate: Biden actually did something that was impossible.

Both sides hate him.

LAURA BARRON-LOPEZ: ... a return to X, the social media platform previously known as Twitter, that banned him after the January 6 insurrection because of the risk of further incitement of violence.

The site's current owner, Elon Musk, who endorsed Trump last month, hosting the former president last night for a high-profile interview.

ELON MUSK, Owner, X: My apologies for the late start.

LAURA BARRON-LOPEZ: But it was plagued with glitches.

Musk, without evidence, blamed a nearly 40-minute delay on a distributed denial of service attack.

Once the stream finally got going, Trump got rambling.

He again praised modern dictators.

DONALD TRUMP: Elon, I know every one of them.

And I know them well.

I know Putin.

I know President Xi.

I know Kim Jong-un of North Korea.

I know every one of them.

They're at the top of their game.

They're tough.

They're smart.

They're vicious.

And they're going to protect their country.

LAURA BARRON-LOPEZ: In stark contrast to Walz's appeal to workers, Trump applauded Musk, who is also the CEO of Tesla, for firing his employees who went on strike.

DONALD TRUMP: Well, you, you're the greatest cutter.

I mean, I look at what you do.

You walk in and you just say, you want to quit?

(LAUGHTER) ELON MUSK: Yes.

DONALD TRUMP: But they go on strike.

They - - I won't mention the name of the company, but they go on strike and you say, that's OK, you're all gone.

LAURA BARRON-LOPEZ: After the comments, United Auto Workers filed federal labor charges against both Trump and Musk.

As for the independent candidate in the race, Robert F. Kennedy Jr. will not be on the ballot in New York.

A judge ruled he falsely claimed residency in the state, despite living in California.

WOMAN: Voting for Reproductive Freedom for All.

LAURA BARRON-LOPEZ: And a major change to the ballot in Arizona and Missouri.

Voters will decide whether to enshrine a right to abortion in their state constitutions, two of eight states so far presenting the issue to voters in November, all this as Connecticut, Minnesota, Vermont and Wisconsin held their primaries today, voters heading to the polls for a say in key congressional races, including Minnesota Representative Ilhan Omar, the latest progressive Squad member fighting a challenge to her seat.

For the "PBS News Hour," I'm Laura Barron-Lopez.