Pelosi most likely wants him as her successor. At the moment she's just waiting out Hoyer. It's kind of mystifying that he's choosing to give that up. Even if you're one of those silly people that think Democrats won't regain the House a single time in 20+ years, even minority leader is arguably a more important/powerful position than a Senator.
Good points. Maybe Van Hollen thinks (assuming he wins) he could climb up Senate leadership?
Yeah, either that or presidential ambitions would be a good explanation.
Just viewed his wikipedia article, Van Hollen was born in Pakistan. No way the GOP would ever let that slide in a Presidential Election.
His parents were American diplomats/officials, there's nothing for even the most die-hard conservative to be mad about.