Maryland Democrats are preparing for a potential open-seat race in the Washington suburbs as Rep. David Trone considers a run for governor. Aruna Miller, a former state House member, filed paperwork this week with the Federal Election Commission, positioning herself to launch a campaign should the second-term Democrat not seek re-election in the 6th District. “Should it become available, I am preparing to run for Congress,” Miller said in an interview. Trone is considering a bid to succeed Gov.