Editor's note: The following is an exclusive excerpt from Professor Paul Kengor’s most recent book, "11 Principles of a Reagan Conservative."

Unlike so many presidents, Ronald Reagan made the job look easy.

Ronald Reagan was born on this day 104 years ago, on February 6, 1911. For many Republicans, Reagan’s birthday has become like Lincoln’s birthday—a time to remember one of their party’s greatest presidents. It seems that every Republican seeking office claims the mantle of Ronald Reagan. “I believe as Ronald Reagan believed,” is a typical Republican mantra.

Unlike so many presidents, Ronald Reagan made the job look easy.

This invoking of Reagan is not surprising. Politically speaking, Reagan was enormously successful. He won the presidency in 1980 by defeating an incumbent in a landslide, winning 44 of 50 states, and then got reelected in 1984 by sweeping 49 of 50 states—including the most liberal among them, from California to Massachusetts, from the entirety of the West Coast to all of New England.

He twice won blue states that Republicans today can only dream of winning. In those two elections, Reagan won the Electoral College by a combined margin of 1014 to 62, and did so when the majority of American voters were registered Democrats. Few presidents enjoyed such decisive success at the ballot box and in office generally. He left the White House with the highest public approval of any president since Eisenhower.

Reagan’s presidential success is all the more notable when juxtaposed to his contemporaries. Dating back to Lyndon B. Johnson, modern presidencies had ended in despair. LBJ, who replaced a president who was killed in office, was destroyed by Vietnam, and decided not to pursue reelection. His successor, Richard Nixon, resigned in disgrace and suffered serious mental and physical repercussions. The office depressed and debilitated Nixon. His replacement, the uninspiring Gerald Ford, was unable to win a single election. Ford promptly lost to Jimmy Carter, whose own presidency was resoundingly rejected; to this day, one senses Carter’s lingering feeling of rejection.

In the other direction, prior to Eisenhower, Harry Truman left office with an approval rating near 20%. He called the White House the “Great White Jail.” Among other 20th century presidents, the job took its toll on Herbert Hoover, Warren Harding, Calvin Coolidge, and William Howard Taft; it ruined Woodrow Wilson, to the point of Wilson suffering several crushing strokes while he was president. Franklin Delano Roosevelt died in office.

After Reagan, George H. W. Bush, Reagan’s vice president and White House successor, won only one term. He was defeated by Bill Clinton, who won two terms but never with more than 50% of the vote, and was impeached. Following Clinton was George W. Bush, who, though likewise winning two terms, had a very difficult presidency. A December 2006 Gallup poll done during Bush’s second term found that Americans considered George W. Bush the most unsuccessful of modern presidents, with an approval rating even lower than Carter and Nixon. Bush registered the highest disapproval of any president since Truman.

And though Barack Obama won two terms, he was the first president in history to be reelected with less popular and Electoral College votes. Obama won a bare majority of states in 2012—only 26 of them. And should we even mention counties? The county map under Reagan was a sea of red, and it remained a sea of red still under Obama.

Unlike so many presidents, Ronald Reagan made the job look easy. In fact, Reagan’s stock has only risen, continuing well beyond his tenure in the Oval Office. In that same December 2006 Gallup poll that revealed George W. Bush’s unpopularity, 64% of respondents judged Reagan an outstanding/above average president and only 10% rated him below average/poor.

Each year, Gallup releases its annual poll for Presidents’ Day, asking Americans to judge the “greatest president” of all time. Gallup began asking the “greatest president” question in 1999. Of the 13 times Gallup has done the survey, the public placed Reagan first four times—2001, 2005, 2011, and 2012—and always in the top three. Reagan typically beats Lincoln.

Many such polls could be cited. A Zogby poll released for Presidents’ Day 2011—the centennial of Reagan’s birth—which asked the public to rate presidents since World War II, listed Reagan as the “greatest,” with FDR second and Kennedy third.

Even then, Reagan’s support transcends the presidency. An extraordinary June 2005 online contest by the Discovery Channel and AOL (which included 2.4 million responses) declared Reagan the “greatest American of all time,” beating Lincoln and Washington.

Reagan also beats Barack Obama. A poll conducted shortly after Obama’s second inaugural asked Americans who they would vote for in a presidential contest between Reagan and Obama. Reagan won in a landslide, taking 58% of the vote, an even higher total than his trouncing of Jimmy Carter in 1980. Remarkably, Reagan even defeated Obama among voters aged 18 to 34, the powerful youth segment that swept Obama into the White House.

In sum, all of this is one way of helping to explain why Ronald Reagan has become the gold standard for Republican presidential nominees. What Republican would not aspire to this kind of public approval? As for liberals who poke fun at Republicans for wanting another Reagan—well, why wouldn’t they?