NurPhoto via Getty Images Nobel Prize-winning economist Paul Krugman said the U.S. was entering an unprecedented "era of corrupt governance."

Paul Krugman is warning U.S. citizens to “stay alert” as the country enters what he believes will be an “unprecedented” era of “corrupt governance” under a Donald Trump presidency.

In a series of tweets on Monday, the Nobel Prize-winning economist described the president-elect as a “profiteer-in-chief,” whose administration would likely distort government policy “in directions that can be monetized.”

Krugman said people should expect “lots of privatization” and a “general shift from transparent to murky so that favors can be traded.” He foresaw the “tilt of U.S. policy toward authoritarian regimes,” which would be more likely to send big business deals to the U.S., he added.

Read all of his tweets here:

We're about to enter, or may already have entered, an era of corrupt governance unprecedented in U.S. history. What does it mean? 1/ — Paul Krugman (@paulkrugman) November 21, 2016

Important to realize that the money stolen by the first family is a minor issue; $10 billion, say, skimmed off the top is rounding error 2/ — Paul Krugman (@paulkrugman) November 21, 2016

What matters much more is the distortion of policy in directions that can be monetized. Gratuitous private investors in infrastructure 3/ — Paul Krugman (@paulkrugman) November 21, 2016

is just the start. Expect to see lots of privatization and a general shift from transparent to murky so that favors can be traded 4/ — Paul Krugman (@paulkrugman) November 21, 2016

And think about the pro-tyrant bias of foreign policy. Democratic regimes -- say, in Europe -- are by their own rules unable to offer 5/ — Paul Krugman (@paulkrugman) November 21, 2016

de facto personal bribes to the U.S. president. Putin's Russia or, for that matter, Xi's China, will be fine with sending huge business 6/ — Paul Krugman (@paulkrugman) November 21, 2016

to the profiteer-in-chief. And that will cause a tilt of U.S. policy toward authoritarian regimes. Stay alert 7/ — Paul Krugman (@paulkrugman) November 21, 2016