“It’s hard to do oversight, especially on counter-intelligence matters, with so little information,” said a Senate Republican Sunday. “That’s been true for months.”

“There is a counter-intelligence investigation focused on Russia, but the media and the Democrats conflate that with there being a criminal investigation focused on Trump,” added a House Republican. “The FBI has fed into this by being coy.”

“Coy” is an understatement. The result of the dozens of questions left unanswered by Comey, Yates, Clapper, and others is that the public — and, to a lesser extent, lawmakers themselves — don’t know the basics of the Russia-Trump matter.

But what to do? Classified information is still classified information. Ongoing investigations are conducted in secrecy (except, of course, for leaks). How can Congress pry information out of the agencies?

“Congress can always coerce the FBI,” said former House Speaker Newt Gingrich in an email exchange Sunday. “Power of the purse. Change the law.”