Sen. Chris Van Hollen is picking up endorsements in his challenge to Chuck Schumer for Senate Democratic leader.Why it matters: The leadership fight exposes divisions within the Democratic Party days after its sweeping midterm victory, with some demanding a new direction and others crediting Schumer for the historic blue wave.Driving the news: Van Hollen (D-Md.), a senator since 2017, announced Thursday he's challenging Schumer because "we need new leadership.""