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KNOW IT ALL: Thursday's Top 8 Stories at NBC News

Here's a look at today's key headlines.

Good morning. Here are some of the headlines we're following this morning:

1. Clinton and Sanders Go Big on Immigration at Florida Debate

Facing questions in English and Spanish at the debate, hosted by Univision and The Washington Post, Clinton and Sanders drew a sharp line in the sand on deportation policies, which could haunt them down the road: Both pledged they would not deport children nor undocumented adults without criminal records. Read more in POLITICS.

2. At Contested Convention, GOP Rules Favor Trump

If Donald Trump fails to win a majority of delegates in the presidential race, some Republican insiders say the party could use a contested convention to deny him the nomination in July. There’s just one problem: The rules for that scenario still favor Trump. Read more in POLITICS.

3. 'Islam Hates Us': Trump Attacks Muslims ... Again

Republican front-runner Donald Trump once again lashed out at Muslims on Wednesday. "I think Islam hates us," the billionaire told CNN's Anderson Cooper when asked whether the religion was "at war with the West." "We have to get to the bottom of it," Trump said. "There is an unbelievable hatred of us — anybody." Read more in POLITICS.

4. Rain to Drench Gulf Coast, South Amid 'Historic' Floods

A ferocious line of thunderstorms responsible for three deaths and that left 25 million Americans facing the threat of floods was set to wreak more misery across the Gulf Coast and South on Thursday. Louisiana, Texas and Arkansas have been hammered all week with downpours, large hail, and at least two tornadoes — and forecasters warned there was more to come. Read more in WEATHER.

5. Five Dead, Three Wounded in Pennsylvania Shooting

Five people were killed and three others were wounded after gunmen opened fire on a backyard party in Pennsylvania late Wednesday, with one of the shooters apparently gunning down victims as they fled for safety, police said. The shooting in the borough of Wilkinsburg just east of Pittsburgh occurred at around 10:54 p.m., police said. Read more in NEWS.

6. Pastor Shooting Suspect Claims Martians Control Earth

Kyle Andrew Odom, the ex-Marine accused of shooting Idaho pastor Tim Remington, was charged Wednesday in Washington, D.C., with being a fugitive after he was arrested while throwing documents over the White House fence. In the documents, Odom writes that "hypersexual" beings from Mars who live underground and inside the moon have been controlling human civilization for millions of years. Read more in NEWS.

7. Pop Warner Settles Major Suit Over Football Concussions

The Pop Warner youth football organization has settled a lawsuit with the mother of a Wisconsin man who she says committed suicide because of brain injuries he suffered playing tackle football beginning at age 11, the organization said Wednesday. Read more in NEWS.

8. NASA Delays Mars InSight Lander Mission to 2018

NASA announced on Wednesday that it has moved back it's next unmanned mission to Mars to 2018, after a component of the Mars spacecraft was found to have a leak in its key science instrument. Read more in TECH.