In political marriages, as in all forms of marriage, the most important messages are often sent indirectly. And when a divisive issue is too threatening to deal with head on, the parties find substitute issues to fight about instead.
So it is in the relationships between executive and legislative powers. We have seen examples in recent days in London and Washington.
This month, the British House of Commons defied Tony Blair for the first time since he became prime minister in 1997. The issue at hand was Blair's demand that the police be allowed to hold terrorism suspects for 90 days without charges, a change from the traditional two weeks.
Blair could easily have had a compromise with the Commons, which eventually raised the limit to four weeks. But he insisted on making 90 days a test of his authority in dealing with terrorists — and so a test of his leadership overall. He lost, and badly. Immediately, Britons began speculating about how long Blair had left and who his successor might be.
Of course, the real source of tension between Blair and his Labour Party was not a matter of days but of British involvement with the United States in the occupation of Iraq. Although some members of Labour's majority are ready to challenge Blair openly on this point, most are not. So the vote on terror suspects served as a surrogate issue, and the message was effectively delivered.
This week, we saw something similar in the U.S. Congress. The Senate attached two notable amendments to the annual bill authorizing the Department of Defense. The first, sponsored by Republican John McCain of Arizona, would require the administration to treat terrorism detainees by the same rules the U.S. applies to conventional prisoners of war.
The Bush administration insists it does not torture detainees and so the McCain amendment is unnecessary. But the administration has also asked for an exemption to the requirement for detention centers run by the CIA. Without such an exemption, the White House says it will veto any bill containing this requirement.
The second amendment that challenged the administration also imposes requirements. It designates 2006 as the year in which Iraq will make a significant transition to self-rule and self-defense, and it requires the administration to produce regular reports detailing how this is happening.
Both amendments passed overwhelmingly, the second after a stronger Democratic alternative (requiring a timetable for the phased withdrawal of U.S. forces) had been rejected on party lines.
The defeat of the Democrats' alternative allowed the White House to declare victory and say it could always supply more reports if that would make the Senate happy. But that did not mean the administration missed the signal the Senate was sending. The Senate is telling the president that his Republican majority remains loyal and wants him to succeed, but that it cannot accept his handling of the situation in Iraq.
In other words, the president may be willing to press ahead while more than 60 percent of the country disapproves of his handling of the war, but other GOP leaders who still need to face voters again are not.
In Great Britain, Blair has dominated his party and his parliament as few prime ministers have in generations. He has done so largely on his charm, intellect and formidable powers of debate. He has also mastered the peculiar tuggings and haulings of history and change in his country's politics, enabling him to use allies and enemies alike to his advantage.
On these strengths, he was able to bring Parliament along on the issue of Iraq. Blair never quite sold his country or his party on the invasion or the occupation, but they had enough faith in him and in his leadership to follow along and even grant him a new term in office.
In the American case, the particular strengths and weaknesses of the executive figure are strikingly different. But the total effect is much the same. The acquiescence of Congress in the invasion of Iraq had less to do with the case for invasion than with the momentum Bush had going with the majority party. And that momentum owed most of its force to the terror attacks of Sep. 11, 2001, and the success of the anti-Taliban campaign in Afghanistan.
In a still broader sense, Blair had accumulated the power to make Parliament go to war by first winning a host of other battles — not the least the elections that brought Labour into power and kept it there. Similarly, Bush stood before the Republicans in Congress in early 2003 as the leader of a national conservative surge, a political movement built on tax cuts and deregulation, on abortion and gay marriage and other sources of political unrest. And, notably, he stood there as their party leader — the man who wrested the White House from the Democrats.
Now in their steadfast insistence on their shared Iraq commitment, Bush and Blair once again resemble each other. They show much the same streak of stubborn self-reliance and they risk much the same fate.
Blair can serve until 2010 if he chooses (although he probably will not); Bush's term is set through 2008. But both are in danger of bringing their time as effective national leaders to an end much sooner, by refusing to accommodate the rebellion against the war among lawmakers and the public at large.