Issue all the subpoenas you want. Nobody is going to show up anyway.
Why wouldn’t they? The coupists know they have top cover from the GOP Senate. Weissmann is running his mouth all over MSNBC, McCabe on CNN, etc. Guilty as sin, free as birds.
Why would they refuse to show? Because of all the Trump administration people who refused to show up when the House subpoenaed them. Turnabout is fair play.