Michael Bloomberg did not hold back on his criticism of Donald Trump in a blistering editorial for his media company, Bloomberg News.

Beginning by saying there are certainly reasons to be optimistic about the upcoming new year, “the increasingly isolated man in the Oval Office is not one of them,” Bloomberg wrote in the op-ed published Sunday.

After ticking off a list of the mind-bending and disturbing events of just the past week — the resignation (and subsequent firing) of respected Secretary of Defense James Mattis, the partial government shut-down (the third this year) over the president’s demand for a border wall, and the stock market’s plunge to its worst week since 2011 — Bloomberg writes that each has a common denominator: “Trump’s recklessly emotional and senselessly chaotic approach to the job.”

Bloomberg, who has indicated interest in running for president as a Democrat in 2020, goes on to argue that Trump’s “decision to withdraw U.S. troops from Syria jeopardized military success in a crucial battle and betrayed an ally as well,” pointing to Mattis’ decision to resign in protest.

He also writes that “Even if a wall were a good idea — and it is not — a government shutdown would be a dumb way to pursue it.”

Bloomberg goes on about his frustration over the partial government shutdown. “This weekend, he imposed needless costs on government workers and on the country at large — not to accomplish anything, or to defend any principle, but to pander to the extreme wing of his party and rage at being thwarted. Republicans in Congress have gone along with this for too long. November should have been a wake-up call.”

He concludes the op-ed with the hope that Republicans in Congress begin to push back against the president. “Unless something changes — unless, in particular, Republicans in Congress start showing some spine — two more years might be enough to test whether we can sustain Trump’s model of bad government. This past week, we got a glimpse of what the beginning of the collapse may look like — and what it may ultimately cost us,” he writes.