Senate Majority Leader Mitch McConnell panned the idea of using a coronavirus stimulus bill to fund major infrastructure investment in a conference call today with Republican senators.

Why it matters: President Trump has been floating the idea — and McConnell is moving early to crush it and more generally, encouraging Republican senators to buck the president's freewheeling spending ideas.

Behind the scenes: On today's call, McConnell said he won't support infrastructure in a COVID-19 bill. "We need to keep the White House in the box," he told senators, according to two sources familiar with the call.

"The Democrats and the White House both need to get the message," McConnell said, according to the sources.

The backstory: This is not the first time McConnell has privately told his colleagues he's uncomfortable with the White House's attitude towards spending.

One of the sources said that on a call with senators last week, "McConnell was essentially saying that, while the president will be willing to spend any amount of money between now and November, it was going to be up to Senate Republicans to act like Republicans and resist crazy spending."

Asked about these comments, a spokesman for McConnell said he did not have anything to read out from the call.

The big picture: McConnell has also been sounding the alarm about spending in his public statements. He said he favored letting states declare bankruptcy, which drew sharp rebukes from prominent Democratic governors such as Phil Murphy of New Jersey and Andrew Cuomo of New York.