I'll go with Kevin Drum for collecting together several point about the way that what he calls the Republican "war on reality" has degraded Congress for twenty years now.
This is from a report yesterday that Republicans had bullied CRS into withdrawing a study about taxes earlier this year, which had Jared Bernstein (justifiably) quite upset yesterday. But as Drum points out, this is just par for the course for Newt-influenced GOP Republicans. Especially worth recalling is the Gingrich-era decision to scrap the Congressional Office of Technology Assessment, which Bruce Bartlett wrote about last year.
The general story in all of this is that the "presidential branch" of government expanded rapidly after WWII, giving the president access to far more expertise than had ever been the case in the past. Previously, presidents would have to rely on executive branch departments and agencies, which could not be trusted to look at things from the president's point of view. Once the presidency grew, Congress reacted by beefing up its own resources. All of this, in my view, was excellent; it allowed elected officials solid, relatively objective evidence about complex policy questions, which tended to prevent the American democracy from being captured by its own bureaucracy.
Of course, as Drum and the others point out, Republicans aren't turning to the bureaucracy for information; they're turning to ideology. Or, more likely, GOP-aligned interest groups. And I have nothing against Members of Congress using lobbyists and party as sources of information. However, neutral sources of information are a terrific way to at least supplement those partisan and self-interested sources, and it's a shame that Congressional Republican haven't outgrown their Newt-era rejection of neutral information. It's bad for them in the long run, and it's awful for democracy.