Donald Trump's shutdown threat is big trouble for Republicans

Without the border wall, Donald Trump might have only been a gold-matted asterisk in the 2016 presidential race. But with the border wall, the longshot real estate billionaire went from political purgatory to 1600 Pennsylvania Avenue.

Given the centrality of his pledge to build a wall along the southern border of the United States (muffled voice: And make Mexico pay for it), Trump is totally committed to ensuring that he can go to voters in 2020 and tell them he made good on that most important of promises. Which is a big, big, big problem for Republicans desperately trying to hold onto their House and Senate majorities in 99 days' time.

"I would have no problem doing a shutdown," Trump said bluntly during a joint press conference Monday afternoon with Italy's prime minister. That bombshell confirmed a Trump tweet from over the weekend. "I would be willing to 'shut down' government if the Democrats do not give us the votes for Border Security, which includes the Wall," Trump tweeted on Sunday. "Must get rid of Lottery, Catch & Release etc. and finally go to system of Immigration based on MERIT! We need great people coming into our Country!"

Those twin pronouncements will land like a rotting fish head at a dinner party for the likes of Senate Majority Leader Mitch McConnell and House Speaker Paul Ryan.

For every second since the last time the government shut down -- in January -- McConnell has insisted it would not happen again.

"The Senate has a lot to do this week," he said from the Senate floor just moments after Trump made his shutdown threat Monday. "We'll finish up the set of appropriations measures we've been considering for several days and take four more big steps towards our goal of completing a regular appropriations process and funding the government in a timely and orderly manner."

McConnell's quote is the essence of envisioning the best possible result in the future, repeating it as much as possible and hoping that it comes true.

McConnell figures if he says "no shutdown" enough, he will keep it from happening. But wishful thinking is not legislation that funds the government. And, with only 11 -- yes 11! -- legislative days between now and the September 30 government shutdown, McConnell knows better than anyone how politically dangerous Trump's threats actually are.