Walter Shaub late Thursday said “we’re in the heads-on-pikes phase of burgeoning authoritarianism” following the GOP-controlled Senate’s vote to acquit President Donald Trump on impeachment charges.

The former head of the U.S. Office of Government Ethics tweeted a list of the moves that Trump and his allies are now making, and the people they are attacking, such as Sen. Mitt Romney (R-Utah), the lone Senate Republican who voted to convict the president over the Ukraine scandal.

Shaub warned: “This is just the start.”

Check out Shaub’s tweets here:

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We're in the heads-on-pikes phase of burgeoning authoritarianism:



- Trump is going after witnesses for testifying to Congress

- Trump and his allies are going after Romney

- Senators, with help from Trump's Treasury Dept., are going after Trump's political rival and his son — Walter Shaub (@waltshaub) February 7, 2020

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- Senators are preparing to go after the whistleblower

- DHS is going after New York

- Barr is investigating DOJ employees for investigating Trump

- Barr issued a policy requiring DOJ investigations of Trump or his political rivals to go through Barr



This is just the start. — Walter Shaub (@waltshaub) February 7, 2020

Shaub has become a fierce critic of the Trump administration since leaving his position within it in mid-2017.

He earlier shared this graphic from the Citizens for Responsibility and Ethics in Washington (where he is a senior adviser) detailing the president’s alleged conflicts of interest during his time in office: