In the wake of President Bush’s commutation of prison time for convicted felon Lewis Libby and a developing constitutional clash over important subpoenas, influential Democratic activists are pressing Congress to put impeachment back on the table.

Today MoveOn.org, the powerhouse group of 3.2 million political activists, launched an unprecedented petition calling on Congress to impeach Vice President Cheney if he defies congressional subpoenas issued to investigate the Bush administration’s purge of prosecutors at the Justice Department. Leading bloggers have also launched a targeted campaign to specifically lobby Democratic members of the House Judiciary Committee to put impeachment back on the table, and as The Nation’s John Nichols reports, some members of Congress say it is now time to "reconsider impeachment proceedings."

The Judiciary Committee is led by John Conyers, who introduced a bill last Congress to explore impeachment proceedings. It drew support from about one out of seven House Democrats at the time. But Speaker Nancy Pelosi said impeachment was off the table during the mid-term campaign, and Conyers later sent an email to his national supporter list echoing the Speaker’s promise.

Leaving aside the detailed debate over when, how and why impeachment proceedings would ever begin, Congress should never have taken the prospect of impeachment off the table. It is a constitutionally protected check against runaway executive power and lawlessness — problems that Americans are quite familiar with lately. (Politicians are fond of reiterating their willingness to keep the option of nuclear bombs "on the table" in foreign policy, so surely constitutional oversight and accountability can remain on the table too.) When Congress tries to govern without its full power, the President can act with impunity. Here’s how the New York Times explained Bush’s commutation today:

Mr. Bush comes at the decision a weakened leader, with his public approval ratings at historic lows for any president, his domestic agenda faltering on Capitol Hill and his aides facing subpoenas from the Democrats who control Congress. Those circumstances offer him a certain amount of freedom; as Mr. Black said, "He knows he’s going to get hammered no matter what he does."

See? Without further consequences on the table, Bush’s historically low support, refusal to work with democratically elected officials in the coequal branch and mounting investigations into serious wrongdoing only serve to give him more "freedom." And with that freedom, Bush and Cheney are fighting to preserve the freedom of a convicted felon, defy congressional investigations and continue to undermine the law and the Constitution through spying, torture and detention policies. How can they be stopped? At times like these, Americans might want to consider what the Founders would do.