The best and worst moments of George W. Bush’s presidency can be found in disasters such as the horrifying massacre last week at Virginia Tech, the deadliest shooting rampage in the nation’s history.

Just over 24 hours after Seung-Hui Cho finished killing 32 people and turning one of his two pistols on himself, the president and the first lady were on the campus in Blacksburg. “It’s hard to imagine that a time will come when life at Virginia Tech will return to normal,” the president told mourners in the packed 10,000-seat coliseum. “But such a day will come. And when it does, you will always remember the friends and teachers who were lost yesterday, and the time you shared with them, and the lives they hoped to lead.”

Off stage, the president individually consoled many of those affected by the tragedy. “I cried when they wanted to cry and I hugged when they wanted to hug,” Bush told CBS News anchor Katie Couric in an interview aired that night.

In the second half of his second term, and with numerous disasters behind him, the president has learned the basics of being “Mourner in Chief.” The first lesson is to get to the scene quickly and spend quality time on the ground.

Bush’s flyover as New Orleans began digging out from Hurricane Katrina two years ago was probably his worst moment in disaster management. Although he landed and toured other affected areas of the Gulf Coast, a photograph of the president gazing down upon the flooded city from inside Air Force One became, for many, a symbol of an administration detached as well as distant from an enormous crisis in the country.

The president’s compassionate, yet forceful, response to the terrorist attacks of Sept. 11 will likely be regarded as his best moment. On the scene Sept. 14, standing over the rubble of the downed World Trade Center, and earlier that same day at the National Cathedral in Washington, the president consoled and rallied the nation with genuine eloquence. And his public approval ratings have never been higher than in the following days.

Reacting to disaster has been nearly an annual event for this president. In 2003, the space shuttle Columbia broke apart, and a teary-eyed Bush immediately went on television to mourn the loss of the seven on board. Four hurricanes ravaged Florida in 2004, prompting Bush to visit five times, personally handing out bags of ice to victims.

Bush, however, has been notably less public in consoling families of soldiers killed in Iraq. He has not attended one of their funerals, although the White House reports that he holds many private sessions with such families.

Expecting a high-profile White House reaction to national disasters is a relatively new phenomenon, but it has taken hold as an important part of the modern presidency. Ronald Reagan had no trouble putting his actor’s training to work in this regard, to especially terrific effect after the space shuttle Challenger exploded in 1986. Bill Clinton nearly perfected the role of national mourner nine years later, when his presence in Oklahoma City after the federal building was blown up boosted his sagging approval ratings. But the first President Bush turned a natural disaster into a political disaster in 1992, when he got hammered for a slow-footed response to Hurricane Andrew in the middle of his failed re-election bid.

If consoling the country in its collective grief has become a president’s duty — one that often directly affects presidential popularity — it makes sense to evaluate how the 2008 White House hopefuls might do in this role. Rudolph Giuliani’s credentials in this department, as mayor of New York City after Sept. 11, are what fuel much of his support for the GOP nomination. Sen. John McCain of Arizona is another Republican with the background to identify with those in pain, having spent five years as a prisoner of war in Vietnam.

Although Sen. Barack Obama of Illinois shows promise as an inspirational figure, among the Democratic contenders former Sen. John Edwards of North Carolina has the most clearly demonstrated success as an empathizer. Once a personal-injury trial lawyer who made a fine living as a champion for victims, he’s focusing his campaign now on a passionate call to aid the downtrodden. He even launched his bid at a still-ravaged neighborhood in New Orleans. And Sen. Hillary Rodham Clinton of New York at least has the most hands-on experience. As first lady, she was at her husband’s side for eight years of closely watched disaster reactions.

For those with no experience, presidential consoling is not a difficult skill to learn. Bush summed it up last week in telling Couric that he just “cried” and “hugged” when needed.

But Lyndon B. Johnson put the most simple and direct words to the task in 1965, when he surprised the victims of another hurricane that had devastated New Orleans. Led by flashlights into a darkened shelter where residents had not even been told that he was coming, Johnson shouted, “This is your president! I’m here to help you!”

Contributing Editor Craig Crawford is a news analyst for NBC, MSNBC and CNBC. He can be reached at ccrawford@cq.com.