What We Know About Kim's Powerful Younger Sister

North Korea's Kim Jong Un promoted his younger sister over the weekend, naming Kim Yo Jong, believed to be 28, to the nation's most important political body, the Workers Party's Politburo. It's a rare sign of trust by Kim in a family member, and the New York Times speculates that he may want to make sure a familial successor is in line should anything happen to him before his young children are old enough to assume power. Related developments:

• Full siblings: Kim Yo Jong and Kim Jong Un have the same parents (their mother was a dancer who was one of Kim Jong Il's wives), and she has for years been seen at her brother's side at public functions, reports Reuters. The pair, along with another full sibling, Kim Jong Chol, who stays out of politics, are believed to have attended school in Switzerland. She is also believed to be married, possibly to the son of a powerful party secretary.
• Blacklisted: In 2014, Kim Yo Jong began working for the ruling party's propaganda arm and thus found herself among those blacklisted this year by the US Treasury Department for "ongoing and serious human rights abuses and censorship activities," per Time.

• Image control? Reports in South Korean media suggest that Kim Yo Jong has been trying to improve her brother's image by encouraging visits to hospitals and such, reports USA Today. She may also be behind his odd friendship with Dennis Rodman.
• Her job: Kim Yo Jong is now an alternate member of the party's decision-making body, which generally rubber-stamps Kim Jong Un's mandates. But she would theoretically get to take part in debates on issues including military decisions. She is only the second woman known to get such an appointment. The first was her aunt, who hasn't been seen in public in years and may be under house arrest. The aunt's husband was executed in 2013, per the Times.
• Taking a toll: Meanwhile, the Wall Street Journal reports that US pressure on Pyongyang is beginning to seriously pinch. More than 20 nations have reduced business or diplomatic ties with North Korea through various means: kicking out ambassadors or guest workers, barring ships, limiting flights, etc. The idea, being pushed by Secretary of State Rex Tillerson, is to try to show Kim that the price for becoming a nuclear power is too high.
• Trump skeptical: One person apparently not sold on the above progress is Trump himself. On Monday, he tweeted, "Our country has been unsuccessfully dealing with North Korea for 25 years, giving billions of dollars & getting nothing. Policy didn't work!"

(More North Korea stories.)