Arizona Republican Sen. John McCain had some choice words for President Donald Trump in a blistering op-ed published just as Congress is getting ready to come back from vacation and face a host of important deadlines.

The Washington Post op-ed is titled “It’s time Congress returns to regular order,” but it is McCain’s knocks on Trump that are getting passed around on social media Friday.

“ Congress must govern with a president who has no experience of public office, is often poorly informed and can be impulsive in his speech and conduct. ” — Sen. John McCain

The GOP senator argues that lawmakers’ work has been complicated by Trump but that regular order — procedural rules that have long governed the Senate — can help advance an agenda including tax reform and an immigration overhaul.

McCain made a similar plea for following those rules during the failed attempt by Republicans to replace Obamacare. McCain was annoyed by GOP leaders’ secretive process in writing their bill and ultimately voted “no,” helping to sink it.

Read:Why John McCain ignored Trump plea and shot down Obamacare repeal.

Trump hasn’t replied to the op-ed — at least on Twitter — but the president has both sparred with and courted the Arizona lawmaker in the past. Trump has ridiculed former prisoner of war McCain but later called him an “American hero” as the Obamacare vote loomed.

After the vote failed, Trump said on July 28 three Republicans and 48 Democrats “let the American people down,” even though he didn’t use McCain’s name.

McCain says in the piece that lawmakers must respect Trump’s authority and cooperate where possible. But, “we don’t answer to him.”

Congress returns to Washington on Tuesday and will plunge into debates including funding the government past Sept. 30, raising the U.S. debt limit and aiding recovery efforts after Hurricane Harvey.

See:From debt ceiling to flood insurance, these are the big deadlines Congress is facing.