Dick Cheney became a one-of-a-kind vice president for two reasons: he cared deeply about governance, and not a bit about his future political standing.

Those same factors, for better or worse, have turned him into a one-of-a-kind former vice president. In a sharp break with long-standing practice, Mr. Cheney has emerged as the highest-profile critic of the new administration....

His role appears all the more striking because it defies normal tidal rhythms of presidential politics. Protocol decrees that when a new administration arrives the old one quietly departs and, at least for a while, defers to its successor by remaining inconspicuous. That pattern has generally held even through dramatic transitions of ideology and political style, as happened when the Democratic incumbent, Jimmy Carter, lost decisively to Ronald Reagan in 1981.

In the first months of the Reagan Revolution, Mr. Carter and his vice president, Walter Mondale, “never attacked us,” Martin Anderson, the White House domestic policy chief under Mr. Reagan, recalled. Such etiquette flowed in no small measure from political realities. Mr. Reagan’s decisive victory in 1980 made it clear that American voters wanted to turn the page.

Former vice presidents often have other reasons for keeping quiet. Mr. Mondale was contemplating his own run for the White House and was intent on presenting himself as a viable candidate, rather than on defending the president he had served. The same held for other former vice presidents eying the presidency: Richard Nixon, Hubert Humphrey, George H. W. Bush, Al Gore.

But Mr. Cheney is an altogether different case. No one expects another campaign from him, freeing him to speak his mind.