PROSPECT HARBOR — Donald Trump will be a one-term president. He will not satisfy the hopes of the “forgotten ones” and America Firsters who got him elected.

Trump supporters – angry older white people from the Rust Belt and rural areas who did not attend college – may stubbornly stick with Trump in spite of the many mistakes he will make, and they will predictably be angered by the protests that Trump’s policies provoke among urban, bicoastal, minority and college-educated Americans. Trump’s base will forget, conveniently, that nearly 3 million more Americans voted for Hillary Clinton than for him. And because all American intelligence agencies now agree that Russian hackers purposely worked to get Putin’s favorite elected, Trump’s legitimacy as president is weak if not endangered.

On the day the Electoral College confirmed his victory, an NBC/Wall Street Journal poll showed that 54 percent of all Americans are pessimistic or concerned about Trump’s presidency. Only 46 percent believe otherwise, a figure that compares unfavorably with Barack Obama’s 68 percent and George W. Bush’s 59 percent support levels following their elections. In brief, Trump does not have a convincing mandate.

Even with Republican majorities in both chambers of Congress – leave alone the deep divisions within the Republican Party – it is doubtful that Trump can be an effective leader.

Add to this Trump’s abrasive, defensive, thin-skinned and egoistic temperament, as well as his proclivity to spout falsehoods, the majority of voters, those who did not support The Donald, are unlikely to remain quiet as he stumbles. And he will stumble; every new president does, but Trump’s political capital is so meager that he cannot count on facing a forgiving public.

Trump’s campaign promises will prove noxious for the economy. If he is able to impose tariffs of 20 percent to 45 percent on Chinese imports, a trade war will likely ensue and result in the loss of hundreds of thousands of American jobs and a spike in unemployment. If Trump’s tax plan is enacted, wealthier Americans will disproportionately benefit and the national debt will increase by an estimated $5 trillion over the next 10 years. If Trump and the Republican Congress eviscerate “Obamacare,” an estimated 20 million to 25 million low-income Americans will lose health insurance coverage and hospital emergency rooms will face unending funding crises.

In all, the same low-income Americans who supported Trump will suffer the most over the next four years and will begin grumbling when they discover that prices of goods at discount stores are soaring. They will start to wonder why they should continue to support the billionaire president and his leadership team of plutocrats and generals.

Trump also promises to renegotiate the North American Free Trade Act and abandon the Trans-Pacific Partnership. NAFTA’s terms permit renegotiation, but their very complexity as well as the economic benefit it has brought to many American corporations will result in pushback from America’s major job-creators and their stockholders. This will, in turn, spark a Republican uprising in Congress, since most Republicans strongly support free trade.

Trump will also face intraparty resistance if he carries through on his Dec. 4 promise to add a tax of 35 percent on all American companies that downsize their local workforce and build factories in other nations. Some in the party will ponder publicly that Trump the businessman does not understand that capital moves to wherever it can maximize profits.

Trump’s promise to “restore prosperity” by protecting millions of low-skilled jobs totally ignores the trend line: The U.S. economy has lost over 30 percent of all manufacturing jobs since 1990, and today fewer than 10 percent of all American workers toil in the manufacturing sector.

Trump can expect an angry reaction to his promise to end the ban on gun-free zones in our schools. Parents everywhere, whatever their views on gun control, want their children’s schools to be free of guns.

Parents also want the air their children breathe to be free of pollutants; hence, Trump’s promises to restore the coal industry will also predictably be met with pushback. Over 70 percent of Americans support clean energy, including 51 percent of all Republicans.

“Campaigning is poetry, governing is prose” is truer than ever for Trump. Trump’s populist campaign messages were music to the ears of his supporters, but President Trump’s actual policies – his prose, as it were – will hurt the very people he has pledged to protect. Massive disillusionment with his failed economic policies could well unite conservatives and liberals to impeach him for misdeeds that may destroy but most certainly will severely weaken the economy.