Ben Roback is a Senior Account Executive at Cicero Group and a member of the US Embassy’s Young Leader’s UK programme.

Investigative reporters had their first major scalp of the Trump presidency in the resignation of Michael Flynn. Opposition Senate Democrats will be pushing for special investigations in unison, and Senators John McCain and Marco Rubio have crossed the aisle to join their calls for scrutiny. Congressional hearings seem certain, but what kind?

The Senate Intelligence Committee could call for an investigation into the allegations that Flynn was in cahoots with the Russians in between the election and Trump’s ascension to the White House. That investigation would take place behind closed doors, and whilst it would be improper to question the strength of its investigatory zeal, it would not be held in the court of public opinion.

What would be more problematic for the White House is the introduction of a special select committee to investigate – a congressional committee that performs a function that is beyond the remit of a standing committee. Crucially, a special select committee would be held in public, creating the opportunity for widespread scrutiny by the press and opposition party.

For an example of just how serious a political crisis a long-running special committee can cause, just ask Hillary Clinton. The special select committee on Benghazi, established by the House of Representatives in May 2014 to investigate the attack on the America embassy in 2012, resulted in eight hours of testimony by former Secretary of State Clinton. Given its proximity to the presidential campaign, Clinton’s run was tainted by her association with the events that led to the loss of four American lives. Democrats on the committee and observers further afar observed that the Benghazi investigation dragged on longer than the inquiries into the assassination of President John F. Kennedy or the attack on Pearl Harbour. The Benghazi example proved the strategically partisan nature that a special select committee can appear to take – and the political damage it can inflict on those most closely associated with it.

The lineation between Senator McCain and the high-level scrutiny of the President and his White House is clear – McCain’s unapologetic opposition to the president has made him a standard-bearer behind whom more moderate Republicans can more quietly align, as this column has argued previously. In short, McCain is a respected and extremely well-known Senator around whom others can corral in less vocal opposition.

That comes with intense political risk, as proven by the President’s rally in Melbourne, Florida on Saturday, where attendees queued for hours to witness the political phenomenon in person. They were quick to give glowing reports of the President’s record in office to date, while sticking to core Trump talking points on political obstructionism and “fake news”. The White House is making life hard for itself though, operating in a way that seems far from the “fine-tuned machine” the president described in his latest 80-minute press conference. According to the Partnership for Public Service, of the 549 key positions requiring Senate confirmation only 14 have been confirmed, with 20 awaiting confirmation and a staggering 515 awaiting nomination. A numerical analysis of previous presidents at this stage shows Trump is behind Presidents Obama, George W. Bush and Clinton. As senior positions in departments go unfilled, civil servants are left to fill the policymaking void.

In what direction can we expect the opposition to take, led by J McCain, the 30-year Arizonan veteran of the Senate? As Chair of the powerful Armed Services Committee, McCain has the platform to continue to be a leading voice on matters of foreign policy, seeking to root Congress in the more traditional Republican approach to international affairs.

McCain will, without fail, continue to be ever-present in front of TV cameras and at high profile global events; only this weekend, he took the opportunity to launch into a scathing new round of criticism at the Munich Security Conference. Then, speaking to Chuck Todd on NBC’s Meet the Press, McCain rejected the suggestion that Trump was “trying to be a dictator,” but would go as far as saying “we need to learn the lessons of history.” It was the kind of lukewarm rebuke that was laced with not-so-subtle innuendo that will become a growing thorn in President Trump’s side. On the Senate floor, McCain will continue to freely vote against the President’s cabinet nominees, having been the only Republican to vote against Mick Mulvaney for Office of Management and Budget Director.

In his campaign for the presidency, Donald Trump issued a stinging rebuke of McCain’s war record, saying “I like people that weren’t captured”. Trump is known for bearing a grudge and remembering those who have dared to criticise him in the past. He may not be the only one. Step forward John McCain, the real opposition.