'Start Here': Giuliani slams subpoenas as Kim Jong Un visits Vladimir Putin

It's Thursday, April 25, 2019. Let's start here.

1. 'Any number of grounds'

As congressional Democrats escalate investigative efforts of the president and his administration, Rudy Giuliani, Donald Trump's personal attorney, says on "Start Here" that the White House "can object to subpoenas on any number of grounds."

"You can only go so far in harassing the president without violating the Constitution," he adds. "They have gone way past that line."

House Democrats this week subpoenaed former White House counsel Don McGahn to force him to testify after special counsel Robert Mueller's report revealed his role as a critical witness in cases of possible obstruction of justice. House Judiciary Committee Chairman Jerrold Nadler, D-N.Y., said he hoped McGahn's testimony would "help shed further light on the president's attacks on the rule of law."

The White House could invoke executive privilege to block McGahn from testifying, but after his extensive cooperation with Mueller's team, it may be too late for that, says ABC News Chief White House Correspondent Jonathan Karl.

"It's hardly 'privileged,'" Karl tells us, "if the public's already read about it in the Mueller report."

2. 'Obsessed with their status'

North Korea's Kim Jong Un traveled 400 miles by train to meet with Russian President Vladimir Putin just two months after Kim's summit with Trump in Vietnam screeched to a halt.

Meetings begin today in Vladivostok, where Kim and Putin will discuss their goals, which could complicate efforts to get the North to denuclearize, ABC News Chief Global Affairs Correspondent Martha Raddatz says on "Start Here."

"This boils down to two leaders who are indeed obsessed with their status on the world stage, their legitimacy on the world stage," Raddatz tells us. "Certainly, what Kim Jong Un wants is for Vladimir Putin to be possibly a spoiler in his hopes that sanctions will be lifted by the U.S."

3. More than words

With ISIS claiming responsibility for the Sri Lanka attacks, authorities are looking at whether the bombings stemmed from more than just ISIS propaganda.

A single bomb-maker likely built the devices that killed more than 350 people on Easter Sunday, and the attack's primary coordinator may not have been in the country when the plan was executed, U.S. officials told ABC News.

"It could've been ISIS-directed or coordinated," ABC News' Aaron Katersky says on the podcast. "In other words, somebody with battlefield experience comes to Sri Lanka or even coordinates with people in Sri Lanka to orchestrate the attack, perhaps from afar, perhaps from within."

4. 'Not going to be comfortable'

Five years ago today, officials in Flint, Michigan, switched the city's water source from Detroit to a cheaper option, the local Flint River.

The water, damaged by outdated city pipes, was discolored and filled with bacteria and lead, but residents were assured it was safe.

Although test results have since shown lower levels of lead as infrastructure has improved, and people can safely drink the water, many residents still don't trust local officials.

"In Flint," ABC News' Stephanie Ebbs tells us, "the problem is that no matter what that level is, a lot of people are not going to be comfortable using the water again."

"Start Here," ABC News' flagship podcast, offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, iHeartRadio, Spotify, Stitcher, TuneIn or the ABC News app. Follow @StartHereABC on Twitter, Facebook and Instagram for exclusive content and show updates.

Elsewhere:

'Unrepentant racist': A white supremacist convicted of murder is executed.

'The longer these outbreaks continue, the greater the chance measles will again get a sustained foothold': Reported measles cases in the U.S. are the highest in nearly two decades.

'As we work through this challenging time for our customers, stakeholders and the company, our attention remains on driving excellence in quality and performance and running a healthy sustained growth business built on strong, long-term fundamentals': Boeing says grounding its 737 Max jets will cost the company $1 billion.

From our friends at FiveThirtyEight:

The man who solved 'Jeopardy!': James Holzhauer has taken the game to its logical conclusion.

Doff your cap:

The California Senate just approved by a 37-0 vote the CROWN (Create a Respectful and Open Workplace for Natural Hair) Act, a measure that aims to end discrimination against people with natural hairstyles, including braids, twists and afros.

The bill initially was passed by Los Angeles Sen. Holly J. Mitchell, who said at a recent speech: "A Google image search for 'unprofessional hairstyles' yielded only pictures of lack women with their natural hair or wearing natural braids or twists."

"Although disheartening," she added, "not very surprising."

SB-188 now moves on to the State Assembly.