As it turned out, the power of the president soared to new heights under Bush. Many of the administration’s most aggressive moves came in the realm of national security and the war on terror in particular. The Bush administration claimed the authority to deny captured combatants — U.S. citizens and aliens alike — such basic due-process rights as access to a lawyer. It created a detention facility on Guantánamo Bay that it declared was outside the jurisdiction of the federal courts and built a new legal system — without any input from Congress — to try enemy combatants. And it argued that the president’s commander-in-chief powers gave him the authority to violate America’s laws and treaties, including the Geneva Conventions.

The assertion and expansion of presidential power is arguably the defining feature of the Bush years. Come January, the current administration will pass on to its successor a vast infrastructure for electronic surveillance, secret sites for detention and interrogation and a sheaf of legal opinions empowering the executive to do whatever he feels necessary to protect the country. The new administration will also be the beneficiary of Congress’s recent history of complacency, which amounts to a tacit acceptance of the Bush administration’s expansive views of executive authority. For that matter, thanks to the recent economic bailout, Bush’s successor will inherit control over much of the banking industry. “The next president will enter office as the most powerful president who has ever sat in the White House,” Jack Balkin, a constitutional law professor at Yale and an influential legal blogger, told me a few weeks ago.

And yet the issue of executive authority scarcely reared its head in the presidential campaign. It wasn’t addressed directly in any of the debates, and aside from a Boston Globe questionnaire on executive authority given to all of the primary candidates in December of last year, neither Obama nor McCain had much to say on the stump or in interviews about the power of the office he aspired to occupy.

“Ambition must be made to counteract ambition,” James Madison wrote, meaning that America’s divided system of government would depend on both the president and Congress forcefully pursuing their respective roles — and in so doing, acting as a natural check on each other. Why did that fail to happen during the Bush years, and will a new president and newly elected Congress act to undo the excesses of presidential power over the past eight years?

Senator Lindsey Graham, the baby-faced South Carolina Republican who first stepped onto the national stage as a House manager of Clinton’s impeachment trial, has not been an easy figure to pin down in the struggle over presidential power. At times, he was one of the Bush administration’s most reliable allies in the Senate, notably when it came to the executive branch’s assertion that it could block enemy combatants from challenging their detentions in federal court. In the fall of 2005, days after the Supreme Court agreed to hear a Guantánamo detainee’s lawsuit against President Bush, Graham came to the administration’s rescue with a bill devised to kick the case off the court’s docket and to make all pending and future detainee challenges illegal. (The bill passed, but the justices nevertheless refused to dismiss the case, Hamdan v. Rumsfeld.)

But Graham, a former Air Force lawyer, was also one of a handful of Republican senators who resisted the executive branch’s claim that the president could authorize coercive interrogations of detainees. He memorably accused Alberto Gonzales, then the nominee for attorney general, of “playing cute with the law” in order to justify that claim and was a member of the triumvirate of so-called Republican mavericks — along with Senators John McCain and John Warner — who drafted a bill aimed at preventing the torture of enemy combatants.

“The Bush administration came up with a pretty aggressive, bordering on bizarre, theory of inherent authority that had no boundaries,” Graham told me one day last summer in his Senate office. “As they saw it, the other two branches of government were basically neutered in the time of war.”