Who is Chris Van Hollen, the senator progressives are pushing instead of Schumer?

Sen. Chris Van Hollen (Maryland) was once entrenched in the Democratic establishment. Now he is on the verge of taking it on.

Van Hollen indicated this week that he is considering challenging Senate Minority Leader Chuck Schumer (New York) to guide their caucus next year as progressive activists — and some colleagues — push for new Democratic leadership in Congress.