ARI SHAPIRO, HOST:

As cavalier as President Trump is being about his relationship with Congress, he's not taking any chances with voters.

(SOUNDBITE OF ARCHIVED RECORDING)

PRESIDENT DONALD TRUMP: Wow, what a crowd.

(CHEERING)

SHAPIRO: His rally last night in Phoenix was an official campaign event, his eighth since becoming president.

(SOUNDBITE OF ARCHIVED RECORDING)

TRUMP: We will make America great again. Thank you, Arizona. God bless you.

(CHEERING)

ROBERT SIEGEL, HOST:

You may remember that Trump wasted no time filing his paperwork to be a candidate for re-election in 2020. He did that on Inauguration Day.

LARRY NOBLE: I'm not aware of anybody who's ever filed that early.

SIEGEL: Larry Noble was general counsel for the Federal Election Commission for 13 years. He's now with the Campaign Legal Center.

NOBLE: President Obama was criticized by some for filing on April of 2011 when the election wasn't until 2012.

SHAPIRO: George W. Bush filed his paperwork in the spring of 2003 for the following year's election. Noble says there are some obvious reasons why Trump may have wanted to start campaigning so soon.

NOBLE: Early fundraising - he can start collecting money as early as possible. He can try to scare away primary opponents. But I think probably most important to him is that he can hold rallies and meetings like he just did where he can control the audience. If you're speaking as president, you have much less control over the audience than if you're speaking as a candidate.

SIEGEL: Along with the rallies where he's selling merchandise, Trump's already making commercials. This one was released last week.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED MAN #1: But President Trump's plan is working - 1 million jobs created, more Americans working than ever before, unemployment lowest since 2001, the stock market...

SHAPIRO: There's also a downside to starting a 2020 campaign in 2017.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED MAN #1: Let President Trump do his job.

TRUMP: I'm Donald Trump, and I approve this message.

NOBLE: What they have to make sure is that the government is not subsidizing any of the campaign events. They also have to make sure that when government - other government officials are speaking, that they don't violate the Hatch Act which prevents them from doing things in their official capacity to support a candidate. So what they have to do is make sure that they have a hard line between the campaign activities that they do and the Presidential Activities that they do.

SHAPIRO: Larry Noble at the Campaign Legal Center says he thinks the Hatch Act was probably violated last night in Phoenix when this happened.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED MAN #2: Please welcome the secretary of the U.S. Department of Housing and Urban Development, Dr. Ben Carson.

SIEGEL: Noble says Carson's government title should not have been used in Trump's campaign rally introduction. HUD Spokesman Raffi Williams tells us he does not believe the law was broken.

(SOUNDBITE OF MR. GREEN'S "COMEBACK") Transcript provided by NPR, Copyright NPR.