Joe Biden hardly brings the glamour and excitement to his ticket that Sarah Palin does to hers, but he surely warmed civil libertarian hearts at the vice-presidential debate when he forcefully denounced “dangerous” theories designed to “aggrandize the power of a unitary executive.” After seven years of an administration that has recognized few, if any, limits on executive power, it’s only natural that many people look to the Obama-Biden ticket to put the presidency back in its proper constitutional place.

But there are good reasons to doubt that an Obama administration would meaningfully de-imperialize the presidency.

From Truman and Johnson’s undeclared wars to the warrantless wiretapping carried out by FDR, JFK, LBJ and Nixon, the Imperial Presidency has long been a bipartisan phenomenon. In fact, our most recent Democratic president, Bill Clinton went even further than his predecessors in his exercise of extraconstitutional war powers. Prior presidents had unilaterally launched wars in the face of congressional silence. But Clinton’s war over Kosovo in 1999 made him the first president to launch a war in the face of several congressional votes denying him the authority to wage it.

Recently, Barack Obama has found his own convenient rationales for endorsing broad presidential powers in the area of surveillance. When he signed on to the surveillance bill Congress passed this summer, Sen. Obama broke an explicit campaign promise to filibuster any legislation that would grant immunity to FISA-flouting telecom companies. By voting for the bill, Obama helped legalize large swaths of a dragnet surveillance program he’d long claimed to oppose. Perhaps some were comforted by Obama’s “firm pledge that as president, I will carefully monitor the program.” But our constitutional structure envisions stronger checks than the supposed benevolence of our leaders.

What motivated Obama’s flip-flop? Was it a desire to look “tough” on national security-or was it that, as he seems ever closer to winning the office, broad presidential powers seem increasingly appealing? Either way, it’s clear that the post‑9/​11 political environment will provide enormous incentives for the next president to embrace Bush-like theories of executive power. Can we really expect a Democratic president, publicly suspected of being “soft on terror,” to spend much political capital making himself less powerful?

Not likely, say analysts on both sides of the political spectrum. Law professors Jack Balkin and Sanford Levinson, both left-leaning civil libertarians, predict that “the next Democratic president will likely retain significant aspects of what the Bush administration has done”; in fact, “future presidents may find that they enjoy the discretion and lack of accountability created by Bush’s unilateral gambits.” Jack Goldsmith, head of the Bush administration’s OLC from 2003-04, argues that “if anything, the next Democratic president — having digested a few threat matrices … will be even more anxious than the current president to thwart the threat.”

There was always something difficult to swallow in the notion that a man running as the reincarnation of JFK could be relied upon to end the Imperial Presidency. Barack Obama has done more than any candidate in recent memory to raise expectations for the office, expectations that were extraordinarily high to begin with. Over the course of the 20th century, more and more Americans looked to the president to perform miracles, from “managing the economy,” to warding off hurricanes and providing seamless protection from foreign threats. As responsibility flowed to the center, the presidency grew far more powerful than the framers of our Constitution had ever intended it to be. We shouldn’t be surprised then, if, during an Obama administration the Audacity of Hope gives rise to the Arrogance of Power.

None of this, of course, is to suggest that a President McCain would be any more respectful of constitutional limits. The Arizona senator worships at the altar of Teddy Roosevelt, maintaining that the bellicose TR was a great president because he “liberally interpreted the constitutional authority of the office.” Like George W. Bush, McCain imagines that the president has a Magic Scepter of Inherent Authority that allows him to ignore statutes like FISA that restrain his discretion in national security matters.

Those who hope to put an end to the abuses of the Bush years are right to distrust McCain. Even so, when it comes to executive power, perhaps the best argument for an Obama presidency is found on a sardonic bumper sticker currently sold at Cafe​press​.com: “Obama ’08: Get Disappointed by Someone New.”

Civil libertarians, of all people, should know better than to hold out hope that a man on horseback will ride in to rescue the Constitution. Eternal vigilance — without regard for person or party — has ever been the price of liberty. That vigilance will be even more necessary in the years to come.