The Congress is checking the WH which forgets, never knew or doesn't care (more likely), that the legislative and executive are co-equal branches of government. Click link to read page 2 of this document.
"They fired Sally Yates. They fired Preet Bharara. And they fired James Comey, the very man leading he investigation. This does not seem to be a coincidence," Schumer said shortly after the announcement, calling for a special independent prosecutor into the Trump campaign's ties to the Kremlin.