President Trump's plan "to move forward in working constructively with Russia" by "forming an impenetrable Cyber Security unit" with the Kremlin to secure American elections came under broad criticism Sunday after early slams from lawmakers on both sides of the aisle.

Sen. John McCain (R-Ariz.) joked in a CBS appearance that Russian President Vladimir Putin could be of "enormous assistance" in improving America's voting cybersecurity "since he is doing the hacking."

Fired U.S. Attorney Preet Bharara also responded with a joke, sarcastically tweeting that during his time at the Justice Department, "When pursuing a corrupt politician, mobster, or murderer on strong FBI evidence, if he 'vehemently denied it,' we just dropped it usually."

Former Defense Secretary Ash Carter was more serious, suggesting on CNN that working with Russia on cybersecurity is like "the guy who robbed your house proposing a working group on burglary." And former CIA Director John Brennan appeared on NBC to castigate Trump for saying it was an "honor" to meet Putin in person. "An honor to meet the individual who carried out the assault against our election?" Brennan asked. "To me, it was a dishonorable thing to say."