Ex-CIA chief John Brennan has become the de-facto leader of the opposition to President Trump.

The son of Roscommon emigrants, usually as cautious as a soldier in a minefield, has come out swinging at this president who he deeply distrusts.

On Monday he used the terms "impeach" and "traitor” in quite remarkable ways for a former top intelligence officer discussing a US president.

Read More: A man in full - exclusive interview with CIA director John O. Brennan

Brennan said Trump's remarks that Putin "was extremely strong and powerful" and his acceptance of Putin’s denial of meddling were "nothing short of treasonous."

Donald Trump’s press conference performance in Helsinki rises to & exceeds the threshold of “high crimes & misdemeanors.” It was nothing short of treasonous. Not only were Trump’s comments imbecilic, he is wholly in the pocket of Putin. Republican Patriots: Where are you???

— John O. Brennan (@JohnBrennan) July 16, 2018

He stated that Trump's action in attacking his own intelligence community and siding with Putin reached the standard of impeachment as "high crimes and misdemeanors."

Why did Trump meet 1 on 1 with Putin? What might he be hiding from Bolton, Pompeo, Kelly, & the American public? How will Putin use whatever Trump could be hiding to advantage Russia & hurt America? Trump’s total lack of credibility renders spurious whatever explanation he gives.

— John O. Brennan (@JohnBrennan) July 16, 2018

Brennan was known as one of the most sobersided officials in the Bush and Obama administration, a man who kept the secrets of his country to himself. A long time Arabist he is widely credited with stabilizing Arab/US relations after 9/11 and helping prevent another 9/11-type attack.

He was among the first fired by Trump when he came into office, called a partisan Democrat but Brennan was nothing of the sort. He was a patriot determined to serve his country as best he could and damn the consequences.

Read More: Trump is "despicable," says former CIA director John Brennan after CIA visit

The son of an Irish blacksmith John Brennan was quick to tell me that his love for his country came from that immigrant dream of his parents who lived to see their son head of the CIA.

The Republican barrage against Brennan has been deafening but even they were reluctant to contradict him. His career has been spectacular and covered both Democratic and GOP presidents.

Brennan had a 25-year career as a spy overseas and a top analyst and executive at home. The shift within the CIA from Cold War focus to the Arab world made Brennan, fluent in Arabic and a Middle East specialist, an invaluable employee.

His career includes stints as station chief in Saudi Arabia, intelligence briefer for President Bill Clinton, top deputy to CIA Director George Tenet during George W. Bush’s presidency, and, then CIA Director, the most highly coveted job in intelligence under Obama.

The sight of Trump kowtowing to Putin, a former KGB agent and now leader of a country with a dreadful record on human rights which blatantly undermined American democracy was the breaking point for many.

Trump hits ex-CIA Director Brennan in Tucker Carlson interview for calling Putin news conference 'treasonous'https://t.co/B61Lml693w

— Sara A. Carter (@SaraCarterDC) July 17, 2018

When Trump answered the AP reporter's question there was a moment of hush, of pure disbelief that he had attacked Hillary Clinton’s emails rather than address the vital matter at hand --did he believe Putin interfere with the US election.

Hillary Clinton is a private citizen living in New York with no impact on foreign policy. The FBI found there were no national secrets released in her tapes, Trump might as well have discussed the impact of new Yankees manager Aaron Boone on the team. The answer had nothing to do with the question.

Read More: Former CIA director John Brennan shows his support for NFL protests 

For once Trump’s incredible skill at bait and switch, of changing the topic when it was uncomfortable escaped him. Instead he looked like a man who had utterly lost the plot as he flailed around and the world press stood shocked.

His refusal to support his own intelligence agency and accept Putin’s assurance was the “worst day ever” in the history of American diplomacy” said former CIA Director Leon Panetta and it leads to one overwhelming conclusion.

Former CIA director and Defense Secretary Leon Panetta says Trump showed “incompetence” when it comes to defending the U.S. interests at Putin summit. Watch the whole interview ▶️https://t.co/Ireh1BJsLr pic.twitter.com/HmhGWItz3p

— Bloomberg TV (@BloombergTV) July 16, 2018

The Russians have the goods on Trump. And he will do everything to avoid them exposing it including running down his own country. What do they have?

The bad guys are winning aided and abetted by our Commander in Chief. Putin is the friend, NATO the enemy. The European Union is our foe and bloody dictators everywhere are the favorite associates of the man in the White House.

Whatever the man in the White House is hiding it is huge. But it will come out. Beware a risen people, Mr. President, they want the truth now more than ever.

Read More: Ex-CIA chief John Brennan says Trump is being played for a fool by Putin