WASHINGTON — President Barack Obama is the fourth sitting president to attend a D-Day anniversary observance in Normandy and the only president to visit the site of the allied invasion twice during his presidency for an anniversary commemoration. It wasn’t always a presidential tradition.

Ronald Reagan was the first, delivering an evocative and emotional remembrance on the 40th anniversary in 1984. Joining him were surviving members of an Army Rangers team that had scaled cliffs at Pointe du Hoc to silence German guns protecting the Normandy beaches.

“These are the boys of Pointe du Hoc,” Reagan said. “These are the men who took the cliffs. These are the champions who helped free a continent. These are the heroes who helped end a war.”

Before him, presidents acknowledged the D-Day invasion with words or statements, but none made a pilgrimage to the site, not even Dwight Eisenhower, who had been the supreme allied commander who ordered the invasion.

Here is a sampling of how presidents observed the key D-Day anniversaries.

DWIGHT EISENHOWER, 10th anniversary, 1954

Issued a statement that reflected the Cold War chasm of the day: “We see peoples, once bitter enemies, burying their antagonisms and joining together to meet the problems of the postwar world. If all those nations which were members of the Grand Alliance have not maintained in time of peace the spirit of that wartime union, if some of the peoples who were our comrades-in-arms have been kept apart from us, that is cause for profound regret, but not for despair.”

Eisenhower did go to Normandy after his presidency, for the 20th anniversary observance.

LYNDON JOHNSON, 20th anniversary, 1964

Johnson, in Washington pushing for passage of the Civil Rights Act of 1964, delivered remarks to members of a D-Day delegation, headed by Gen. Omar Bradley: “Your country remembers and will never forget, the resolve born on that D-Day, that, so long as we are able, and other men are willing to stand together, we shall not permit the light of freedom to be extinguished on any continent again. … So let all the world know that when this nation has stood 2,000 years we shall not have forgotten the lands where our sons lie buried, nor the cause for which our sons died. Where we have commitments to the cause of freedom, we shall honor them — today, tomorrow and always.”

RICHARD NIXON, 30th anniversary, 1974

Nixon, in the throes of the Watergate investigation and with impeachment hearings underway, sent Gen. Bradley once again to the ceremonies. Five years earlier, Nixon had issued a proclamation on the 25th anniversary calling the Normandy assault “a historical landmark in the history of freedom.” He also met at the White House with former war correspondents who were on their way to France for the 25th anniversary observance.

RONALD REAGAN, 40TH anniversary, 1984

Reagan spoke at the top of the cliffs of Pointe du Hoc, the Atlantic Ocean spread behind him and with 62 gray-haired surviving Rangers seated before him.

“They shot rope ladders over the face of these cliffs and began to pull themselves up. When one Ranger fell, another would take his place. When one rope was cut, a Ranger would grab another and begin his climb again. They climbed, shot back, and held their footing. Soon, one by one, the Rangers pulled themselves over the top, and in seizing the firm land at the top of these cliffs, they began to seize back the continent of Europe. Two hundred and twenty-five came here. After two days of fighting, only 90 could still bear arms.

“Behind me is a memorial that symbolizes the Ranger daggers that were thrust into the top of these cliffs. And before me are the men who put them there.”

BILL CLINTON, 50th anniversary, 1994

Clinton attended the 50th anniversary, delivering his remarks at the U.S. Cemetery in Colleville-sur-Mer, France. His comments offer an ironic reference point to the Europe that Obama faces as he arrives in Normandy on Friday.

“Fifty years later, what a different world we live in. Germany, Japan and Italy, liberated by our victory, now stand among our closest allies and the staunchest defenders of freedom. Russia, decimated during the war and frozen afterward in communism and cold war, has been reborn in democracy. And as freedom rings from Prague to Kiev, the liberation of this continent is nearly complete. Now the question falls to our generation: How will we build upon the sacrifice of D-Day’s heroes? Like the soldiers of Omaha Beach, we cannot stand still. We cannot stay safe by doing so. Avoiding today’s problems would be our own generation’s appeasements. For just as freedom has a price, it also has a purpose, and its name is progress.”

GEORGE W. BUSH, 60th anniversary, 2004

Bush went to Normandy in 2002 to observe Memorial Day. He returned for the 60th anniversary, speaking at the U.S. cemetery and accompanied by French President Jacques Chirac.

“All who are buried and named in this place are held in the loving memory of America. We pray in the peace of this cemetery that they have reached the far shore of God’s mercy. And we still look with pride on the men of D-Day, on those who served and went on. It is a strange turn of history that called on young men from the prairie towns and city streets of America to cross an ocean and throw back the marching, mechanized evils of fascism.”

BARACK OBAMA, 65th anniversary, 2009

Obama recalled that his grandfather, a 26-year-old supply sergeant stationed near the English Channel, crossed the channel six weeks after D-Day and followed allied forces across France.

“At an hour of maximum danger, amid the bleakest of circumstances, men who thought themselves ordinary found within themselves the ability to do something extraordinary. … That is the story of Normandy — but also the story of America; of the Minutemen who gathered on a green in Lexington; of the Union boys from Maine who repelled a charge at Gettysburg; of the men who gave their last full measure of devotion at Inchon and Khe San; of all the young men and women whose valor and goodness still carry forward this legacy of service and sacrifice.”