Andrew Romanoff was once a rising star of the Democratic Party here in Colorado, the youngest speaker in the history of the Colorado House and apparently assured of a bright future. Today he is rattling the doors of the party establishment that used to be his home, The Washington Post reports. Romanoff finds himself in the role of the uninvited guest because he has chosen to challenge Sen. Michael Bennet in the Democrats’ Senate primary. In a year in which the party is on the defensive, officials are not enthusiastic about challenges to vulnerable incumbents, which Bennet is. Democratic voters will have to decide who would be the stronger candidate in the general election.