This is no ordinary election. Time for a reminder of what's at stake:

Climate policy and the clean-energy economy: For anyone who accepts the scientific consensus that global warming poses a clear and present danger, there is only one choice. Hillary Clinton will continue along the path laid out by President Obama and other world leaders. Donald Trump has claimed, ridiculously, that climate change is a hoax invented by the Chinese.

For the first time, the three nations most responsible for spewing heat-trapping carbon dioxide into the atmosphere -- China, the United States and India -- have all formally agreed to curb emissions. The landmark Paris agreement is the biggest and most important step taken to date. Clinton would honor the accord; Trump would renounce it on his first day in office.

The rest of the world is moving rapidly toward renewable sources of energy, which recently surpassed coal as the largest global source of power-generating capacity. According to the International Energy Agency, last year an estimated 500,000 solar panels were installed worldwide every day. Clinton would encourage the growth of the clean-energy sector, which has the potential to create millions of jobs. Trump promises a renaissance of fossil fuels -- mining more coal, pumping more oil -- even though the electric-power industry is moving on.

The Western alliance: Since the end of World War II, NATO has been the globe's most important military alliance, a bulwark against Soviet -- now Russian -- expansionism and a source of peace and prosperity. It is no accident that the United States and Europe are the world's biggest economic powers.

Clinton may be a bit hawkish for some tastes, but she is firmly committed to the NATO security framework. Trump describes NATO as if it were a protection racket.

Trump has repeatedly and consistently expressed a desire for an alliance with Russia, even after it seized Crimea from Ukraine and intervened to save the murderous regime of dictator Bashar Assad in Syria. Trump often voices his admiration for Russian President Vladimir Putin -- who, according to U.S. intelligence analysts, has deployed an army of internet hackers against the Democratic Party in a shocking and unprecedented attempt to meddle in our election. Trump has done nothing to refute Clinton's claim that he would be Putin's "puppet" in the White House.

Immigration reform: An estimated 11 million undocumented immigrants live here, most of them from Mexico and Central America. Clinton supports commonsense immigration reform that would secure the southern border, modernize our system of legal immigration and bring the undocumented out of the shadows by giving them legal status and a path toward citizenship. Trump does not.

Trump launched his campaign by saying of Mexican immigrants: "They're bringing drugs. They're bringing crime. They're rapists. And some, I assume, are good people." He has called for building a physical wall along the entire border with Mexico, and absurdly claimed that Mexico would somehow pay for it. And he pledges to deport all of the undocumented, in what would amount to a massive campaign of ethnic cleansing. Doing so would require a gargantuan and intrusive deportation force the likes of which this country has never imagined, let alone witnessed.

The social fabric: The country is undergoing a process of inexorable demographic change. By 2044 if not sooner, according to the Census Bureau, there will be no racial or ethnic majority; non-Hispanic whites, in other words, will be less than 50 percent of the population, becoming a minority just like every other group. This is already the case in California, Texas, New Mexico and Hawaii; and nationwide among children under 5.

Clinton understands and embraces these changes. Trump, by contrast, has become the champion of those whites who, like King Canute, would hold back the sea. It is no accident that he is avidly supported by the likes of David Duke, the unabashed white nationalist, Holocaust denier and former imperial wizard of the Ku Klux Klan. When Trump says "Make America Great Again," many minorities hear "Make America White Again."

Fiscal sanity: Clinton proposes new spending -- including to improve the Affordable Care Act -- that would increase the national debt by $250 billion over the next decade, according to the bipartisan Committee for a Responsible Federal Budget. Trump's combination of huge tax cuts and increased spending, however, would balloon the debt by a crushing $10 trillion over the same period.

I could go on, but you get the point. Donald Trump gravely threatens our future. He must be stopped.

(c) 2016, Washington Post Writers Group