The progressive veterans group VoteVets was in the middle of what one member called a regular activity Tuesday morning — calling out the President of the United States on Twitter — when it suddenly hit a virtual wall.

The Commander in Chief can block @VoteVets, the voice of 500k military veterans and families, but we will NOT be silenced. pic.twitter.com/SaCN5hKU9R — VoteVets (@votevets) June 13, 2017

“As I was tweeting him, I went to reply to one, and it said the tweet was no longer available,” Will Fischer, an Iraq War veteran and director of government relations for the group, told TPM in a phone interview Tuesday. “I clicked on @realDonaldTrump and it said that we had been blocked and were no longer able to follow the President’s Twitter.”

“Despite the fact that Sean Spicer has said that these are official statements from the President of the United States,” Fischer noted.

The President’s tweets are more than official statements, some lawyers for blocked Twitter users have argued — they constitute a public forum. The replies beneath Trump’s tweets have become valuable, and competitive, political real estate, alternately used to mock the President, goad his followers and promote oneself.

There’s some evidence Trump reads them, too. On Tuesday, for example, the President retweeted one of the responses, boosting it to his 32 million followers.

The White House did not respond to TPM’s questions about the block. And Fischer said VoteVets hadn’t yet spoken with lawyers about whether the President had infringed upon their First Amendment rights.

“But do I subscribe [to the idea] that he’s trying to quell free speech? Yes,” Fischer said, describing what he called the the President’s dream of “his own alternate universe that is sort of a dystopia for the rest of us, in which every opinion he has is correct.”

“He is a thin-skinned charlatan,” he added. “Donald Trump seeks to quell dissent and to surround himself only with sycophants who are going to shower him in praise and adoration.”

On Tuesday morning, Fisher said, “the tweet that broke the snowflake’s back” was a response to the President’s criticism of “Fake News Media,” which Trump said had driven an “agenda of hate.”

Vote Vets sent its last tweet, at least for now, to their commander-in-chief:

You're describing your road to the White House to a T, @realDonaldTrump. Well, this and colluding with an adversary of the United States. — VoteVets (@votevets) June 13, 2017

It was the last of eight responses to the President Tuesday morning, criticizing everything from his attempted bans on travel from several Muslim-majority countries to his praise for Philippine President Rodrigo Duterte, whose extrajudicial war on drug users and dealers has so far left thousands dead.

B/c your Muslim ban is unconstitutional, immoral, & a threat to our nat'l security. You are a threat to our nat'l security, @realDonaldTrump — VoteVets (@votevets) June 13, 2017

While we're on it, @realDonaldTrump, the way you treat our allies is a threat to our nat'l security. — VoteVets (@votevets) June 13, 2017

The way you, @realDonaldTrump, praise homicidal maniacs like Duterte is a threat to our nat'l security. — VoteVets (@votevets) June 13, 2017

The way @realDonaldTrump fawns over and fan dances for Putin is a threat to our nat'l security. — VoteVets (@votevets) June 13, 2017

The cavalier way @realDonaldTrump speaks a/b sending young women and men to war (not HIS kids) is a threat to our nat'l security. — VoteVets (@votevets) June 13, 2017

@realDonaldTrump's climate change denials (despite the opinion of SecDef Mattis) are a threat to our nat'l security. — VoteVets (@votevets) June 13, 2017

@realDonaldTrump, the way you and your family violate the Emoluments Clause is a threat to our nat'l security. — VoteVets (@votevets) June 13, 2017

The group’s account spent the rest of the day re-upping support from the Twitterverse, some of whom had themselves been blocked by the President.

Fischer said VoteVets, which bills itself as the largest progressive group of veterans in America, wasn’t worried about making its message heard.

‘We have 500,000 members in all 50 states,” he said. “We think we’ll be able to get that done.”