The Democrats are a minority in both houses of Congress. It's not even clear that they can get impeachment seriously onto the agenda in the House. Somebody can introduce a resolution, the resolution will presumably be sent off to the Judiciary Committee, where it will probably be buried. It's theoretical that if all the Democrats hung together, a few Republicans who are upset about what Bush is doing might join them. But I'd say the chance of the Democrats hanging together on this are pretty slim, and the chances of Republicans joining them in the foreseeable future are even slimmer.