After nearly six years of being treated by the White House as an inconsequential nuisance — a casual dismissal of its relevance in which it was too often complicit — Congress now has an excellent opportunity to finally reassert itself as the constitutionally equal branch of government intended by the nation’s founders.

The House Judiciary Committee has approved a contempt of Congress resolution in response to former White House counsel Harriet Miers’ decision to ignore a Congressional subpoena to testify in connection with the committee’s investigation of charges that the Justice Department has been inappropriately politicized, plus the refusal of White House Chief of Staff Josh Bolten to produce relevant documents. The question here is not whether the charges are valid but whether Congress is entitled to look into the matter in connection with its own constitutional obligations.

Ms. Miers claims that as a former member of the president’s staff, she is protected by “executive privilege” from being required to testify. But the privilege exists to shield communications between a president and his advisers and is designed to ensure a president’s ability to receive candid advice; in this case, the White House concedes that the president was not involved in any of the discussions under investigation.

What is being put forth is essentially a ludicrous, and dangerous, claim that no member of the White House staff can be questioned about any conversation with anybody about any subject. Bolten made a similar claim in refusing to produce documents under subpoena (although the Congressional Research Service has documented more than 70 instances in which presidential advisers, including previous holders of Ms. Miers’ position, have come to Capitol Hill to testify). The White House also has insisted that there be no transcripts of any interviews, that no internal White House documents can be reviewed and that if the committee conducts interviews or reviews documents received or sent by the White House, it must agree not to ever seek any further information, no matter what the interviews or documents reveal. No Congress, indeed no lawyer, would ever agree to such an outrageous demand.

Republicans, members of my own party, who have traditionally insisted on constraining government power and whose party platforms have repeatedly called for checks on the presidency, have been remarkably acquiescent, apparently placing a misguided sense of party solidarity ahead of the oaths they swore to uphold the Constitution.

If Congressional leaders are not able to persuade the administration to reverse its position and allow Ms. Miers to testify and Mr. Bolten to produce documents, then all Members of Congress, regardless of party, should insist that the subpoenas be enforced promptly and vigorously and to use civil litigation if, as the White House has hinted, it prohibits the D.C. U.S. attorney from performing his enforcement duties.

The most disturbing facet of these emerging controversies is the fact that throughout the debates in both the House and Senate, Republicans have remained largely silent, just as they did earlier when the House Judiciary Committee looked into presidential assertions of the right to disobey laws the president himself had signed into being.

To remain silent in the face of presidential aggrandizement is not to defend George W. Bush, it is to betray the American people who, regardless of which party controls the government, rely heavily on the people they elected to ensure that this nation’s unique form of constrained, citizen-empowered government remains strong.

And that requires defending Congress — not a Democratic or Republican Congress but the peoples’ Congress — as a separate, independent and completely equal branch of government.

Former Rep. Mickey Edwards (R-Okla.) chaired the House Republican Policy Committee and is a lecturer at Princeton University’s Woodrow Wilson School of Public and International Affairs.