Senate Minority Leader Chuck Schumer warned Tuesday that Democrats are worried President Trump might fire Attorney General Jeff Sessions in the coming days, and then try to replace him through a recess appointment over the August break, when the Senate is out.

But in a Senate floor speech, the New York Democrat said Democrats would be taking steps to prevent that from happening.

"Many Americans must be wondering if the president is trying to pry open the office of attorney general to appoint someone during the August recess who will fire Special Counsel Mueller and shut down the Russia investigation," he said.

"Democrats will never go along with the recess appointment if that situation arises," he said. "We have some tools in our toolbox to stymie such action, we're ready to use every single one of them, anytime, day or night."

Under the Constitution, the president is allowed to bypass the Senate's advice and consent role when the Senate is in recess, and appoint people on his own. Recess appointees eventually have to be confirmed by the Senate if they are going to stay in their position, but a recess-appointed attorney general could serve Trump for more than a year.

Republicans worried for years that President Obama would recess appoint objectionable Cabinet officials, and to stop him, they refused to formally take the Senate out of session, and instead held occasional pro-forma sessions.

Obama eventually declared that the Senate was effectively in recess and made a recess appointment to the National Labor Relations Board. But the Supreme Court ruled that Obama's appointment was illegal because the Senate was not in recess.

Schumer and Senate Democrats could use the same tactic against Trump, by refusing to adjourn the Senate for the August recess, and force it to hold occasional pro-forma sessions.

Schumer also warned that Republicans in the Senate shouldn't try to help Trump make a recess appointment.

"I cannot imagine my friends on the Republican side, and particularly in the Republican leadership, my friend the majority leader, who I have great respect for, and Speaker Ryan," Schumer said. "I can't imagine they would be complicit in creating a constitutional crisis."

"They must work with us and not open the door to a constitutional crisis during the August recess," he added.