'Start Here': Trump nixes Iran strike, war crimes trial 'bombshell,' SCOTUS-palooza

It's Friday, June 21, 2019. Let's start here.

1. Rising tensions

Tensions between the U.S. and Iran have ratcheted up even further after a U.S. military drone was shot down off the Iranian coast.

President Donald Trump ordered a military strike on Iran on Thursday night, but reversed his decision after a plan was underway, sources familiar with the matter told ABC News.

The president's reason for changing course was unclear, sources said, and the Trump administration's response has yet to be determined, according to ABC News Chief Global Affairs Correspondent Martha Raddatz.

"I don't think this is going to be an all-out war," Raddatz says on "Start Here." "Nobody wants an all-out war, but the concern here is what happens if the United States does a proportional response. Does that end it?"

While Republican congressional leaders called for a "measured response" against Iran on Thursday, Senate Minority Leader Chuck Schumer was among Democrats who warned that the Trump administration "may bumble into a war."

"I think Democrats are concerned that the president may make some kind of a knee-jerk reaction without thinking through the full ramifications," ABC News Senior Congressional Correspondent Mary Bruce tells us. "Democrats are also being very clear that whatever the president does, he must get the approval of Congress."

2. 'Bombshell'

U.S. Navy SEAL Chief Edward Gallagher, a sniper and a medic, is on trial for allegedly murdering a captured ISIS fighter, but in a stunning twist, a fellow SEAL medic who'd been granted immunity testified that he was responsible for the killing.

When prosecutors called Special Operator 1st Class Corey Scott as a witness, Scott told the court that while he saw Gallagher stab a wounded teenage ISIS fighter, it was he who killed the teen by putting his own hand over the 17-year-old prisoner's tracheal tube to suffocate him.

ABC News' Maria Villalobos was in the courtroom when it happened: "I looked at everybody because I thought, 'Did I just hear this? Am I imagining this?' This is a bombshell."

3. 'Transcended'

The Supreme Court today is expected to hand down a number of decisions, including one about whether the Trump administration can add a citizenship question to the census, that have to be delivered before the end of the term.

The court ruled on Thursday that a 40-foot World War I memorial cross could remain on public land in Maryland. Despite the monument's use of a Christian symbol, ABC News Supreme Court Contributor Kate Shaw says the court's rationale is that the nearly 100-year-old memorial has "transcended its religious origins."

"Because the meaning of this is about commemorating the fallen, not just about religious symbolism, that is reason enough for the court to decide not to order the cross to be taken down," she tells "Start Here."

"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:

'They have not found the phone': A key piece of evidence is missing in the case of a man who accused Kevin Spacey of sexual assault.

'It would be a catastrophe': Vladimir Putin talks about potential ramifications of a U.S.-Iran military conflict.

From our friends at FiveThirtyEight:

The USWNT is on to the next challenge -- with an eye on France: The 2-0 scoreline doesn't reflect it, but the Americans dominated the Swedes from the first whistle to the last. They possessed the ball 61% of the match and created 13 scoring chances. Sweden, on the other hand, created just four chances and rarely looked threatening otherwise.

Doff your cap:

Some firefighters in Colorado used a YouTube video to rescue some ducklings ... is not a sentence written very often.

But written today it shall be!

0:42

Firefighters play YouTube clip to rescue ducklings

A first responder played duck sounds on his cellphone to coax frightened ducklings out of a storm drain pipe.

ABCNews.com

"Since fire engines aren’t equipped with duck calls," South Metro Fire Rescue tweeted after its rescue effort, "Firefighters used the audio from a @YouTube video to talk 4 frightened ducklings out of a storm drain pipe."

They were reunited with their siblings and mother after the operation concluded ... swimmingly.