The Congressional Black Caucus plans to walk out en masse from the House chamber during the vote today to hold Attorney General Eric Holder in contempt of Congress. The CBC believes that the contempt vote is a ploy to embarrass the President and his Administration. They are circulating a letter to get other Democrats to join them outside the chamber during the contempt vote.

The letter urges Democrats to stand up for Holder, who is black and who is the first U.S. attorney general in history to be charged with being in contempt of Congress. Republican leaders are moving forward with the vote because they say Holder is withholding certain documents relating to their probe into the Justice Department’s botched Fast and Furious operation. Holder has provided 7,600 documents so far and said he can’t provide certain others because it would violate confidentiality rules. The White House and congressional Democrats maintain that the GOP-led effort is purely political.

“Contempt power should be used sparingly, carefully and only in the most egregious situations. The Republican Leadership has articulated no legislative purpose for pursuing this course of action. For these reasons we cannot and will not participate in a vote to hold the Attorney General in contempt. We adamantly oppose this partisan attack and refuse to participate in any vote that would tarnish the image of Congress or of an Attorney General who has done nothing but work tirelessly to protect the rights of the American people. We must reflect upon why we are elected to this body and choose now to stand up for justice,” reads the letter.

The obvious subtext is that an African-American Attorney General serving under an African-American President is being singled out by the House GOP, with a contempt vote of a Cabinet member being held for the first time.

Not every Democrat will join the CBC. Several, in fact, plan to vote for the contempt resolution, particularly after the announcement that it will be scored by the NRA. As many as 30 Democrats could cross the aisle on the vote, a sign that the gun lobby matters far more than partisan loyalties.

There will actually be two votes today:

The House will consider two resolutions. The first would ask the U.S. attorney in Washington to file a criminal case to force Holder to comply with the subpoena. The other would permit the House to hire an outside attorney to file a civil lawsuit asking a judge to compel Holder to cooperate.

Otherwise, a contempt resolution likely would die once it was sent to the U.S. attorney, who works for Holder and likely would not force his boss to comply because Obama has asserted executive privilege to keep the documents sealed.

The NRA is pressing for the contempt resolution because they believe in a conspiracy theory, that the Fast and Furious operation allowed guns to travel across the border into the hands of Mexican cartels in an elaborate ploy to provide support for increased gun control. The only bill signed in the Obama Presidency having anything to do with guns expanded gun rights by allowing firearms in national parks.

A long story in Fortune magazine yesterday, with the cooperation of members of the Bureau of Alcohol, Tobacco and Firearms, alleged that the entire Fast and Furious scandal was not a gun-walking operation at all, but a botched attempt to crack down on “straw purchasers” (who buy guns for others), stymied by loose statutes in Arizona and overly cautious Obama Administration federal prosecutors who didn’t authorize arrests.

The contempt vote concerns documents that House Oversight Committee Chair Darrell Issa wants handed over by Holder’s Justice Department. The documents largely concern internal DoJ deliberations on how to handle the Oversight Committee’s Fast and Furious investigation, so it’s once removed from the scandal. Issa admitted yesterday in the House Rules Committee that Holder didn’t authorize the Fast and Furious operation. The President put these documents, separate from the 7,600 DoJ documents already provided to the committee, under executive privilege, which deserves scrutiny because the rationale for the action has not been well articulated.