On April 3, 2018, President Donald Trump will welcome to the White House the presidents of Estonia, Latvia, and Lithuania in a reaffirmation of ties between the three Baltic nations and the United States. Those three nations, along with many others, suffered for many decades as Soviet vassal states behind the Iron Curtain.

Exactly fifty years ago, Ronald Reagan made his own first official foray into the geopolitics of Eastern Europe. The path started by Reagan is today being followed today by his fellow conservative and Republican heir, Donald Trump.

Historian Paul Kengor's The Crusader reviewed the anti-communism of early Ronald Reagan. But several new historical discoveries merit further discussion. In a previously unknown 1962 GOP marketing recording, spearheaded by former president Dwight Eisenhower, "Mr. Lincoln's Party Today," narrator Reagan — a recent convert to the Republican Party — modified Lincoln's famous "House Divided" speech. Reagan updated it to discuss a world divided, between the West on one side and the Soviet Union and its vassals: "The world cannot exist half slave and half free."

Two years later, just before the general election landslide victory of Democrat Lyndon Johnson, the floundering Barry Goldwater campaign asked actor Reagan, also the national spokesperson for General Electric, to address the nation. In his famous televised speech, "A Time for Choosing," Reagan castigated the West: "We never open up our mouths about the millions of people enslaved in Soviet colonies ... A billion now in slavery behind the Iron Curtain." He argued that it would be immoral to tell these people to give up their dreams of freedom because the West would buy their own security by bargaining with the Soviets, but would forget about Eastern Europe.

During 1965-1967, Reagan was actually being mentored on domestic politics and world affairs by Eisenhower. This would have many lasting consequences. At the end of a May 15, 1967, debate on Vietnam with Robert Kennedy — which Reagan won, in a major boost to his first presidential campaign at the time — the subject matter shifted and Reagan for the first time proclaimed that the Berlin Wall should be "knocked down." During other campaign stops in 1968, Reagan repeated that first public push to tear down the wall, which he would repeat in front of the wall itself 19 years later.

Other than giving speeches, what else could then-Gov. Reagan, running in his first presidential campaign, do to help bring freedom to Eastern Europe? The answer arose in the spring of 1968. He decided that even though he was just a governor, he would find a way. And although history has forgotten what Reagan did on April 4, 1968, His action never was forgotten by the peoples imprisoned behind the Iron Curtain.

Reagan did not zero in on a Baltic country, but instead it was another region behind the Iron Curtain: the Balkans.

At the time, Croatia and neighboring Slovenia, under the heel of communist Josip Broz Tito's Yugoslavia, were objecting to rising taxes — music to the ears of conservative Reagan. On April 4, 1968, in the presence of Tadija "Ted" Pavich (who had spent fifteen years in Tito's prisons), Father Peter Topic (who had fled from Tito's troops in 1945), and a local California Republican assemblyman, Gov. Reagan signed a proclamation honoring Croatia's prior independence:

"Whereas Croatia is presently subjugated to force and terror by Yugoslavia which has prevented the election of representatives to the Sabor and has deprived Croatians of the basic human rights of self-determination, free elections, economy, culture, religion, and even language ..."

Reagan added that some 150,000 Americans of Croatian descent were living in California and were "always maintaining their vigilance against Communist aggression." Reagan then proclaimed April 10, 1968, as Croatian Independence Day and invited "all citizens to give renewed devotion to the just aspirations of all people for national independence and human liberty."

Americans of Croatian descent, along with their families behind the Iron Curtain, had been electrified by Reagan's proclamation and did not forget what Reagan had done. The next month, at an important campaign stop in Cleveland on May 22, Reagan would be greeted by a huge throng waving banners of thanks from America's Croatian communities.

Meanwhile, the Yugoslavian ambassador was not pleased. President Johnson was starting to see the threat posed by presidential candidate Reagan. Incredibly, muckraking columnist Drew Pearson, a close confidant of Johnson, attacked Reagan's proclamation by asserting that Croatians and other Eastern Europeans imprisoned behind the Iron Curtain should thank the occupying Red Army for providing "protection," since they did not have to pay for their own defense!

But for the most part, history would forget Reagan's first official call for freedom in Eastern Europe. For later on the very day he issued his proclamation, as he flew east for a planned speech in the nation's capital, the captain came back to inform him of the assassination of Dr. Martin Luther King, Jr.

Upon his return to California, Reagan found another way. This time he turned north, to the imprisoned Baltic states. A group of dancers from the Latvian Folk Ensemble of New York was visiting California, and Reagan accepted their album.

Reagan's mentor Eisenhower had been the first to proclaim Captive Nations Week on July 17, 1959 and a similar proclamation was to be made yearly until "freedom and independence shall have been achieved for all the captive nations of the world." On June 30, 1981, President Reagan delivered the first of his eight Captive Nations Week proclamations. He said that America reaffirmed that "free men and women will ultimately prevail over those who deny individual rights and preach the supremacy of the state." As reviewed by historian Lee Edwards, Reagan would become the first president to hold a public White House ceremony to mark Captive Nations Week. Reagan told listeners trapped behind the Iron Curtain that their cause was not forgotten.

President Reagan made a startling new proclamation on June 14, 1982, by becoming the first American president to usher in "Baltic Freedom Day," to commemorate June 14, 1941. That was the day when, nearly two years after Adolf Hitler handed the Baltic states to Josef Stalin in the Molotov-Ribbentrop Pact, the first of hundreds of thousands of Baltic nationals were deported to Russian prisons and forced labor camps, and Russian settlers took over their homes and jobs. Reagan looked ahead to a day when "the blessings of liberty will one day be part of the national life of the courageous people of Estonia, Latvia, and Lithuania."

He followed through by having his United Nations ambassador deliver a strong message about the Baltic nations in July 1983: "We cannot remain silent in the face of the continued refusal of the government of the USSR to allow these people to be free."

A few months later, on Nov. 18, 1983, to commemorate Latvian Independence Day, President Reagan inaugurated Radio Liberty to reaffirm that the United States did not recognize the forcible and unlawful incorporation of the Baltic States into the Soviet Union. Historian Lee Edwards reviewed the chain of events started by the Reagan Doctrine. First came the "Singing Revolution" of the late 1980s, when two million Estonians, Latvians, and Lithuanians joined hands across the Baltic States demanding freedom. Soon enough, in the summer of 1991, when this last region gripped by the Soviet Union was freed, the Baltic and Balkans all cheered their new-found freedom as they watched the USSR collapse into the ash heap of history.

Today, much of what Presidents Eisenhower and Reagan envisioned has come to fruition. The Iron Curtain and the Berlin Wall have fallen. Freedom has been reclaimed for millions in Eastern Europe. The Baltic nations have joined NATO and the European Union. And statues, streets and parks honoring Ronald Reagan appear all over Eastern Europe.

President Barack Obama did an about-face when he stopped America's defensive missile shield from including Poland and the Czech Republic, two of the nations freed in that process. Fortunately, President Trump has reversed that decision.

When Vice President Mike Pence visited the Baltics on July 31, he reviewed how proud America was for the support the Baltic states have shown in fighting the Islamic State and in Afghanistan.

And Trump issued his first Captive Nations Week proclamation on July 14. In it, he honored his Eisenhower and Reagan. Reiterating a theme used many times by those earlier presidents, President Trump reminded America that "Freedom is a powerful, yet fragile force that must be tirelessly protected."

The millions of citizens formerly trapped behind the Iron Curtain, and those millions still imprisoned under repressive regimes in other areas of the world, can take solace that America once again has a leader in Trump who will carry forth the mantle of liberty, which he inherited from fellow Republicans Abraham Lincoln, Eisenhower, and Reagan.

Historian Gene Kopelson is the author of Reagan's 1968 Dress Rehearsal: Ike, RFK, and Reagan's Emergence as a World Statesman (Figueroa Press, 2016).