Karl Rove has had more political power and more opportunities to employ it than any other presidential adviser in recent history. His tenure at the White House, to end this month, was marked by an omnipresent campaign for a permanent Republican majority and an inability to turn electoral wins into successful legislation.

Mr. Rove showed repeatedly that he knows how to capture elections. In 2000, he helped George Bush into the White House through a Florida recount that left the country badly divided. In 2002, Republicans unusually gained more seats in a midterm election, and in 2004, when the Bush administration’s foreign policy was being rewritten (for North Korea and Iran), with the war in Iraq getting worse and with domestic policy at a standstill, President Bush still won a huge number of votes and re-election. Even in defeat last year, when the primary GOP achievement over the last six years had been tax cuts that favored the wealthy, the margin of victory for Democrats was slight.

But the difference between winning 51 percent of the vote and passing legislation is vast, and Mr. Rove’s combination of bravado and attack that worked in campaigns did not have the same result in Congress, especially the Senate. With the exception of the No Child Left Behind education reforms – which depended on the support of Democrats Sen. Edward Kennedy and Rep. George Miller – the administration has failed to pass broad changes to social programs. The collapse of Social Security privatization was apparent from the minute it was announced; new rules for illegal immigration faltered repeatedly. Medicare expansion passed but not Medicare reform – the program is less affordable now than ever. Now, with a Democratic majority, reauthorization of NCLB’s core changes is in doubt.

In President Bush, Mr. Rove found a leader who allowed him to assert an agenda based on grand themes, and in the aftermath of 9-11, the administration found its chance to carry them out. Six years later, the nation has a president who insists he has broad executive authority to ignore Congress, heightened official secrecy, new and expanded eavesdropping rules and a Department of Homeland Security that has yet to prove itself. The war in Iraq, once the administration’s example of using might to do right, has now been so thoroughly redefined that a good day in Baghdad is one in which fewer people were killed than were the day before.

Mr. Rove will exit, pursued by a Congress that wants to talk to him about the firing of U.S. attorneys and anything else it can find. He will follow other prominent White House officials, such as counselor Dan Bartlett, budget director Rob Portman and chief White House attorney Harriet Miers. But none of them seemed as central to Bush’s presidency, and none left with the sense that an essential part of the White House was leaving with him.