Mr Brennan, who was director of the Central Intelligence Agency under former president Barack Obama, has been a sharp critic of Mr Trump, frequently appearing on cable television news shows to attack his foreign policy positions.
Trump's action Wednesday in stripping Brennan of his security clearance demeaned "one of the finest public servants I have ever known", McRaven wrote.
Mr Brennan sought to reassure his "Irish brothers and sisters" that the United States is a strong country, but at the moment President Trump is "not upholding the image and reputation of what it means to be an American president. we're gonna get there but we have some rough waters to navigate", he said. Trump said hours after Brennan's clearance was being revoked.
The only question remaining is whether the collusion amounts to a "constituted criminally liable conspiracy", Brennan wrote.
Even by the standards of angry Trump-era criticism, Brennan's words represent an unprecedented attack by America's normally hush-hush spooks on a political leader.
Turkey raises tariffs on US-origin products
The Turkish lira plummeted to a record low against the dollar this week, falling to 7.24 before recovering slightly. Turkey took the action in response to what it called the Trump's administration's attack on its economy.
"So I think it's something that had to be done", he added.
Brennan, a persistent critic of Trump, lashed out at the president for calling former White House aide Omarosa Manigault Newman a "dog" in a tweet, saying "it's astounding how often you fail to live up to minimum standards of decency, civility & probity".
On his Twitter account, Trump reposted several comments supporting his revocation of Brennan's clearance, including one from Sean Hannity, a conservative Fox News television host. Legal experts said the dispute may add to the evidence being reviewed by special counsel Robert Mueller.
In an op-ed published by the Washington Post, McRaven, a former Navy SEAL who led US Joint Special Operations Command from 2011 to 2014, not only called Brennan "a man of unparalleled integrity", but volunteered to have his own security clearance revoked in an act of solidarity.
Shortly after they sent out the first statement, the White House released a second, identical statement that was undated.
Tencent profit drop blamed on wait for new games approval
China has frozen approval of new game licenses amid a government shake-up, people familiar with the matter said this week. The art style was changed, but the game went on to be a huge success both in Tencent's native China and North America.
"You look at any of them and you see the things they've done", Trump told the Journal. "The Hillary Clinton whole investigation was a total sham".
There was no reference to the Russian Federation probe in a White House statement Wednesday that was read at a press briefing and then sent out to reporters. "I think that they're very duplicitous".
Trump later changed again, tweeting that he "never fired James Comey because of Russian Federation!"
That directly contradicted a July 2017 statement from Trump Jr. - written with the consultation of the White House - that claimed the meeting had been primarily about adoption.
Former PSU quarterback Christian Hackenberg signs with Philadelphia Eagles
"He is being evaluated by team doctors as part of the concussion protocol", Tomlin said . This is the first time since 2015 that Roethlisberger entered concussion protocol.