A quarter-century after the fall of the Soviet Union handed the United States victory in a titanic ideological duel, the era's mythology is echoing through a presidential election taking place in a new age of fear and threats.

Republican nominee Donald Trump drew an analogy Monday between dangers once posed by the Soviet Union and the more recent peril of Islamic terrorism.

"In winning the Cold War, President Ronald Reagan repeatedly touted the superiority of freedom over communism and called the USSR the Evil Empire," Trump said in a major speech in Ohio. "Just as we won the Cold War in part by exposing the evils of communism and the virtues of free markets, so too must we take on the ideology of radical Islam."

The billionaire went on to mine the Soviet-obsessed 1950s to find a new approach to battling terrorism, particularly in the elaboration of his expanded policy on Muslim immigration.

An 'ideological test'

Trump called for a return to the "ideological test" introduced in 1952 for aliens attempting to move to the United States. And he called for "extreme vetting" to stop the infiltration of potential radical Islamists.

"In addition to scraping out all members of the sympathizers of terrorist groups, we must also screen out any hostile attitude towards our country or its principles, or who believed Sharia law should supplant American law," he said.

The Republican presidential nominee's evocation of a black-and-white age when the identity of the enemy was obvious and when US power was at its apex suits his political style -- which emphasizes tough talk and harshly taking down adversaries.

But it also fits with the historical inflection point of 2016, as US global supremacy is being challenged by a host of rising and revitalized powers -- not just one -- and Americans' anxieties stem in part from questions about the US's future primacy as a world leader.

In one sense, Trump appeared to be reaching back to the Cold War for a time when America's enemies were well defined, unlike the constantly evolving and fear-inducing terror threat from groups abroad like ISIS and the homegrown radicals that they inspire.

The Cold War was also a time of fear -- sparked by the real possibility of nuclear annihilation. Yet in retrospect, the period is now remembered with some fondness, as it ended in an American triumph forged by a galvanized populace and successive administrations of different political stripes that deployed American values and power to great effect.

While there are some similarities between then and now, there are key differences, particularly in geopolitical terms. Some experts believe that comparing the war on terror to the struggle against Soviet communism is unhelpful.

From superpower to regional rivals

"There are some resemblances to the Cold War in America's current circumstances, but they have nothing to do with terrorism or ISIS or al Qaeda," said Michael Mandelbaum, professor emeritus at the School of Advanced International Studies, saying that a 25-year period when the United States faced no great power rival was now drawing to a close.

"Now we have returned to a period of rivalries," said Mandelbaum, author of "Mission Failure: America and the World in the post-Cold War Era." He noted that it features an "ambitious China and an aggressive Russia and an Iran which is resolutely anti-American seeking to become a dominant power in the Middle East."

But Trump's nostalgia for the Cold War only goes so far, and in a sense that's surprising.

After all, a former KGB operative who called the fall of the Soviet Union "a tragedy" is running the Kremlin, has Moscow pursuing its most aggressive post-Cold war foreign policy and stands accused of meddling in the US election with an espionage hacking operation targeting Democratic leaders.

Yet Trump instead has praised Russian President Vladimir Putin, seeming to have regard for his strongman style of leadership and ability to assert himself on the world stage, perhaps seeing a template for the kind of figure he would like to cut in international diplomacy.

This is one reason why Trump's use of Cold War imagery to address the threat from terrorism fails to convince some critics, who believe that the billionaire's true aim is to stoke a much more sinister suspicion of aliens that has emerged at various points in US history.

This critique suggests that in singling out Muslims for new immigration checks, Trump is again seeking culprits for America's woes and trying to put a face on a new enemy that could capture public opinion and enhance his political power base.

In various periods, anarchists, Chinese workers, criminals, communists, Japanese, German and Italian immigrants have been the target of measures ostensibly meant to protect Americans.

Some Trump critics see the GOP nominee's speech on Monday as simply the latest illustration of a political method that relies on singling out culprits and enemies to bolster his own political base.

"What he is doing is thousands of years old. It goes back to the most ancient native danger of pure democracy that the founding fathers were extremely aware of and designed the Constitution against," said Michael Signer, an academic and author who is now Charlottesville's mayor.

Signer, who wrote a book on demagogues -- a category in which he places the billionaire -- said such politicians play to prejudices to set up a power base that follows them and them alone.

"For Trump, that generally has meant trying to create many different enemies of the American people," Signer said. "The enemies have ranged from Mexicans to women to Muslims to immigrants in general to Hillary Clinton supporters to certain states even."

A time of 'national crisis'

But Trump supporters defend his approach.

Kansas Secretary of State Kris Kobach told CNN there was nothing wrong, for instance, in conducting examinations at the port of entry of potential immigrants.

"You have a presumption that the individual does not get in unless certain boxes can be checked," he told CNN's Kate Bolduan. "We are in a time of national crisis just like we were in 1952."

Corey Saylor, a spokesman for the Council on American Islamic Relations, pointed to one major difference, however.

"The ideological tests during the Cold War were for political ideology," he said. "Is this ideological test going to be driven from whatever this panel decides is acceptable Islam?"

Still, there is another major force feeding the Cold War overtones in the 2016 campaign -- the brooding presence of Putin himself.

The Russian leader's international mindset was framed as he watched the humiliation of the Soviet collapse from dissolving East Germany as a KGB agent.

As president, he has often seemed to embrace a foreign policy based on the idea that what is bad for the United States is good for Russia -- or his personal political interests -- in a way that is not that different from a Cold War zero-sum game.

"I think he would be delighted if he and Russia are at the center of American politics and Russia is regarded as the great disruptive force," said Mandelbaum.