Like it or not, the decision we make in this November's election will be a choice on behalf of the entire world. How we vote will determine whether the forces of democracy, openness and religious tolerance remain strong, or whether our country throws in its lot with tribalism, prejudice and authoritarianism.
This sounds like melodrama. It isn't. And while it may ring familiar — citizens of other countries always tell us how important our electoral verdicts are to them — Donald Trump requires us to make a judgment more monumental than any we have faced in our lifetimes.
This is the underlying import of President Obama's speech to the United Nations on Tuesday, which may prove to be one of the most important of his presidency. He spoke of a "growing contest between authoritarianism and liberalism," and he was not referring to the L-word we fight about here at home, but to the philosophy of free expression, entrepreneurialism and participatory decision-making that has long been our country's hallmark. It's the philosophy that most Americans, conservatives included, honor.
Obama cast the matter this way: "We can choose to press forward with a better model of cooperation and integration. Or we can retreat into a world sharply divided, and ultimately in conflict, along age-old lines of nation and tribe and race and religion."
He criticized "a crude populism — sometimes from the far left, but more often from the far right — which seeks to restore what they believe was a better, simpler age free of outside contamination."
And lest anyone miss that he was talking not only about political currents in Europe and elsewhere but also about Trump, he added this: "Today, a nation ringed by walls would only imprison itself."
Obama's critics have every right to question whether his policies may have hastened this moment of decision. In a normal election, contention over Obama's approach to foreign affairs would be central to our debate.
But this is not, in any way, a normal election. Conservatives who have problems with Obama or Hillary Clinton but share their understanding of the country's democratic obligations need to recognize that allowing Trump to win would strengthen the autocratic Vladimir Putin in Russia and the far right in Europe with which he is now allied. A Trump victory would also empower violent extremists in the Islamic world that want nothing more than for the United States to cast every Muslim as our enemy.
And it would be a decision in favor of what Obama called the "strongman, a top-down model, rather than strong, democratic institutions."
The fact that Trump has been so verbally chummy with Putin should be a key issue in this election. And this underscores the unusual importance of Trump's making his tax returns public, as have all recent candidates. Americans need to know definitively whether or not he is financially entangled with foreign interests hostile to the United States and to our values, including Russian oligarchs.
There was a second level to Obama's U.N. speech that should affect our thinking after this election is over. After issuing an enthusiastic defense of an open global economy, he was careful not to dismiss those who have risen up in protest against its injustices. He argued that "those trumpeting the benefits of globalization have ignored inequality within and among nations" and that "the existing path to global integration requires a course correction."
He forcefully called for strengthening labor unions, echoed Pope Francis in criticizing "a soulless capitalism that benefits only the few" and insisted that efforts "to curb the excesses of capitalism" were designed "not to punish wealth, but to prevent repeated crises that can destroy it."
I do not expect conservatives to rally to this part of his case, although I would like them to take more seriously the idea that preserving the very aspects of the system they revere requires more egalitarian public policies and a clear acknowledgement of capitalism's limits.
This, however, represents the sort of healthy quarrel that people of goodwill in free nations can have with each other after the immediate threat that Trump represents to the democratic left, right and center alike has been turned back.
I know it asks a great deal of my conservative friends not only to oppose Trump but also to support Hillary Clinton. But she is the only person standing between us and a United States that abandons our shared commitment to the ideals of inclusion, toleration and, yes, democracy itself.
E.J. Dionne's email address is email@example.com. Twitter: @EJDionne. He is a native of Fall River. Distributed by Washington Post Writers Group.