5 things for Tuesday, June 20: Otto Warmbier, House race, Supreme Court

Why does North Korea detain some US citizens?
Why does North Korea detain some US citizens?

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Why does North Korea detain some US citizens? 01:17

(CNN)Today is World Refugee Day, and it comes as the world faces the worst refugee crisis in history. Here's what else you need to know to Get Up to Speed and Out the Door. (You can also get "5 Things You Need to Know Today" delivered to your inbox daily. Sign up here.)

1. Otto Warmbier

Otto Warmbier has died, less than a week after coming home to the US from detention in North Korea. The heartbreaking loss of the 22-year-old college student evoked grief from his family and anger from the highest levels of the US government. Secretary of State Rex Tillerson said the North Koreans would be held "accountable" for unjustly detaining Warmbier; Sen. John McCain said the regime "murdered" him with treatment so harsh he was left with brain damage. Also now, the tour group that took Warmbier to North Korea in 2016 will end trips there for Americans.
    3 Americans still being held by North Korea
    3 Americans still being held by North Korea

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      3 Americans still being held by North Korea

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    3 Americans still being held by North Korea 00:52

    2. US politics

    Donald Trump isn't on the ballot, but his presence looms large today as the most expensive House race in history ends. Parties and super PACS have spent more than $50 million in the special election in Georgia's 6th congressional district, in Atlanta's northern suburbs. It pits Democrat Jon Ossoff and Republican Karen Handel in a runoff that many see as a referendum on the popularity of the President. It may give us the first sign of whether Trump's sagging poll numbers could be a threat to the GOP's control of the House in the 2018 elections.
    Democrats hope to turn Georgia's 6th blue
    Democrats hope to turn Georgia's 6th blue

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      Democrats hope to turn Georgia's 6th blue

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    Democrats hope to turn Georgia's 6th blue 05:26
    Meanwhile, up in DC, Democrats spent last night giving speeches from the Senate floor to protest the behind-closed-doors process the GOP is using to craft the chamber's version of a health care bill.

    3. Supreme Court

    The high court will take up a Wisconsin gerrymandering case, the most important case of its kind in a decade. It involves district lines in Wisconsin that challengers say were drawn to help Republicans. How the Supremes rule on this one could impact how district lines are drawn nationwide.
    Does gerrymandering cause polarization?
    Does gerrymandering cause polarization?

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    Does gerrymandering cause polarization? 03:34
    Also, the court struck down two laws: one banning registered sex offenders from Facebook; and another blocking disparaging trademarks, a ruling sure to please the Washington Redskins.
    Meanwhile, the 9th Circuit Court of Appeals cleared the way for a key part of President Trump's revised travel ban to go forward. The administration can now conduct internal reviews of other countries' vetting processes for visa applicants. The most controversial parts of the ban, however, remain blocked as the whole thing makes its way to the Supreme Court.

    4. Terror attacks

    The suspect in the city's latest terror attack is Darren Osborne of Cardiff. Police say he was behind the wheel of the van that mowed down pedestrians near a mosque in north London. Osborne reportedly shouted, "I did my bit, you deserve it." Eleven people were injured, and one man, who was receiving first aid when the attack unfolded, was found dead at the scene.
    How Muslims feel after the Finsbury Park attack
    How Muslims feel after the Finsbury Park attack

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    How Muslims feel after the Finsbury Park attack 01:22
    And that wasn't the day's only terror incident involving a vehicle in Europe. In Paris, along the famed Champs-Elysees, a car deliberately rammed into a police van. The driver, who was armed, was pulled out of the car by police before the car burst into flames. He later died; the car was packed with explosives.

    5. Weather

    The heat is on out West, where it's so hot that American Airlines has canceled about 50 flights in and out of Phoenix as the temperature there hit 118 degrees. Hotter air means planes need more speed (and more runway) to take off. Las Vegas may see its highest temperature ever recorded, while temperatures today in Phoenix (119 degrees) and Death Valley, California (127 degrees) will be scorching, as well. If that's not enough molten misery, wildfires are burning across California, which is also dealing with buckling roads and power outages caused by the increased use of air conditioners.
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    What NOT to do in a heat wave

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    BREAKFAST BROWSE

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    Thermal thaw
    It's raining in Antarctica, and if that sounds weird, well yeah, it is. Here's more weird: an area on the continent twice the size of California is melting. Not good.
    Pint-sized perspectives
    While adults debate "Wonder Woman's" brand of feminism, the kids in one kindergarten class are happy to let the Amazon warrior change their view of the world.
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    Space sweepers
    There are about 170 million pieces of space debris floating around our little planet. That's a lot of junk. Now a Japanese company has a plan to clean it up.

    NUMBERS OF THE DAY

    1,297
    The number of children killed annually by guns from 2012 to 2014, a new study finds
    200 million
    That's how many registered US voters had their personal information accidentally leaked online by a GOP analytics firm

    AND FINALLY ...

    She will rock you
    Dave Grohl invited his 8-year-old daughter to the stage and let her drum along as Foo Fighters covered a Queen classic. (Click to view)