I love the comment from House Select Benghazi Committee Chairman Trey Gowdy to his Republican colleagues.

“Shut up” about things about which you know nothing, says the South Carolina Republican.

They know nothing? Or do they know, um, too much?

Hillary Clinton is going to testify this week before the House panel about the fire fight in September 2012 at the U.S. consulate in Benghazi, Libya. Four brave Americans died in the melee, including the U.S. ambassador to Libya.

Republicans have been trying like the dickens for more than three years to find enough dirt on Clinton, who was secretary of state at the time, to pin something on her. They’ve accused her of covering something up.

They’ve come up empty … so far.

House Majority Leader Kevin McCarthy then popped off about the reason the committee was formed, noting that Clinton’s poll numbers have plunged since the panel began its work; his comments seemed to most observers to suggest the motive for the committee being formed in the first place was to torpedo Clinton’s presidential campaign.

And then came Rep. Richard Hanna, another GOP colleague, to say the same thing that McCarthy said. D’oh! There’s another one: Bradley Podliska, a former GOP staffer — who worked for the Benghazi committee — also said the same thing. He doesn’t know, Mr. Chairman?

Clinton’s testimony could sink her campaign. It could lift it to new heights. As some folks have noted, the Benghazi hearings have gone on longer than the House Watergate hearings and the Warren Commission hearings looking into JFK’s assassination.

One of these days, hopefully before the presidential nominating conventions next year, the Benghazi panel will wrap this up, publish its findings and then we can move on.