Vice presidents usually sing in harmony, if not in unison, with their boss. But there are times when the No. 2 voice in the administration is most effective in counterpoint.
Vice President Dick Cheney has been especially effective in this role, often playing the "bad cop" when President Bush has chosen a softer, more sympathetic tone.
So it was again this week, when the two men defended the administration's goals and policies using highly disparate styles.
In his national address and news conference this week, President Bush several times struck a note of humility. He admitted mistakes had been made and said he understood the questioning and the criticism prompted by bad intelligence leading up to the war in Iraq and by revelations of domestic, warrantless surveillance of U.S. citizens.
But while the president sounds conciliatory, the vice president continues to make his arguments in his own way. And that means there's not a whiff of humility nor an ounce of effort to mask intention.
This was the message when the vice president met with reporters covering his trip to the Middle East this week. Reporters on one flight asked about the big story back in Washington. Did the administration really have the right to pursue domestic surveillance without a warrant? Cheney provided a history lesson -- much of which he could say he learned first hand.
He complained that the 1973 War Powers Act, which put restrictions on the president's authority to launch military action without congressional approval, was "an infringement upon the authority of the president." The law, Cheney said, may be "unconstitutional."
Cheney noted that what he called these "limitations" on executive power were put in place during the denouement of the Vietnam War and the early phases of the Watergate scandal. A weakened President Richard M. Nixon vetoed the bill but Congress overrode that veto. The following year, Nixon resigned.
Cheney served in the administration of Nixon's successor, Gerald R. Ford, rising to be White House chief of staff. He saw the effects of the hamstrung presidency at close range.
Later, as a U.S. House member from Wyoming, Cheney was part of the congressional investigation of the Iran-Contra scandal. That controversy arose because officials of Ronald Reagan's administration went around the 1982 law limiting U.S. assistance to anti-communist guerrilla groups in Central America.
When the Iran-Contra probe produced its report in 1987, Cheney's staff helped write the dissenting minority report. He says that dissenting document was "very good in laying out a robust view of the president's prerogatives."
According to the minority report, the White House made some "mistakes" during the scandal, which transferred funds weapons sales to Iran to support the Contras in Nicaragua. But some of the mistakes, it said, "resulted directly from an ongoing state of political guerrilla warfare over foreign policy between the legislative and executive branches."
The report laid much of the blame on the opposition: "Congressional Democrats tried to use vaguely worded and constantly changing laws to impose policies in Central America that went well beyond the law itself," the report said. "For its own part, the Administration decided to work within the letter of the law covertly."
Working "within the letter of the law covertly" is one way to describe the recent actions of the Bush administration regarding the handling of detainees and the gathering of intelligence. Critics of the administration have questioned whether these covert actions were in fact "within the letter of the law," much as investigators did in the Iran-Contra case.
After raising the report in his session with reporters, Cheney summed up by saying that, especially in the area of national security, "the President of the United States needs to have his constitutional powers unimpaired."
He added that he and President Bush have worked hard in their five years in office to make sure those powers are unimpaired, and that he believes they've had some success.
Few would quibble with that assessment. Their success began in the early days of 2001 and the struggle over the task force on energy policy. Democrats wanted to know who was advising the White House on the issue, but Cheney, who ran the panel, refused to disclose the names.
He and President Bush insisted that people serving in the executive branch have a legal right to get private advice from whomever they want. To divulge details of such discussions, their argument went, would make advice-givers less willing to speak candidly.
Ever since, the administration's devotion to its prerogatives and control of information has been its hallmark.
"I do think that to some extent now, we've been able to restore the legitimate authority of the presidency," Cheney said.
The phrase "to some extent" gives an idea of where the White House wants to go in the future. Observers of the president and vice president never doubted this was their thinking. But it falls to the vice president to articulate it so plainly.