Maybe President Bush recently watched that Schoolhouse Rock video in which a curious boy asks a hopeful bill sitting on Capitol Hill how "even if the whole Congress says you should be a law, the president can still say no." Or maybe he discovered his veto pen while he was packing for his move out of the White House at the end of next year.

But I suspect the president's decision to stand up for fiscal responsibility by threatening to reject appropriation bills he considers too extravagant has something to do with the fact that his party no longer controls Congress. Likewise the legislative branch's sudden enthusiasm for challenging the president's expansive view of executive power. I was pleased by the Republican defeat in last fall's congressional elections, and so far my hope that blind partisanship would serve the cause of limited government seems to have been vindicated.

The Democrats say Bush's new interest in controlling spending is just a pose, that the amount of money involved is trivial. But for a president who has surpassed Lyndon Johnson in discretionary spending, who championed a huge expansion of Medicare, and who has vetoed only two bills in six-and-a-half years, even pretending to care about fiscal restraint is an improvement.

The Democrats' attempts to rein in executive power may be more consequential. In January, even before the new congressional majority held a single hearing on the National Security Agency's warrantless surveillance program, the Bush administration announced that it would henceforth seek judicial approval for monitoring international communications involving people on U.S. soil, as required by the Foreign Intelligence Surveillance Act (FISA).

Complying with FISA, which the administration had insisted would jeopardize national security, somehow became feasible after the Republicans lost control of Congress. Now the Democrats want to know why the president thought obeying the law was optional. The Senate Judiciary Committee (with the support of three Republican members) recently issued a subpoena demanding Justice Department documents that may shed light on the administration's legal rationale for the warrantless surveillance program.

In a sense, we already know the rationale: When it comes to fighting terrorism, the president believes he has the constitutional authority to do as he pleases. But the substance of internal administration disagreements about the surveillance program's legality remains obscure.

In May, former Deputy Attorney General James Comey testified that he refused to sign off on a renewal of the program in 2004. Comey, who at the time was in charge of the Justice Department because Attorney General John Ashcroft was recovering from emergency gall bladder surgery, said White House Counsel Alberto Gonzales (now the attorney general) and Chief of Staff Andrew Card tried to go over his head, appealing to Ashcroft as he lay in his hospital bed.

Perhaps hallucinating phantoms of lost liberty under the influence of post-surgical pain medication, Ashcroft backed up Comey, although he ultimately gave his blessing to the surveillance program after it was modified to assuage his concerns. To arouse the objections of John Ashcroft, who was notoriously dismissive of civil libertarian complaints about the administration's anti-terrorism policies, the program must have been pretty far over the line.

Among other things, members of the Senate Judiciary Committee would like to know what Ashcroft's concerns were, why they came up only after the program had been operating for three years, and how they were addressed. They may also be wondering how the Bush administration is now able to comply with FISA, why the administration still wants Congress to change the law, and why it did not ask for those changes years ago.

The Democrats are performing an important public service by pressing questions like these, even if they are mainly interested in embarrassing the other party and gaining an electoral advantage. I'd prefer a principled commitment to civil liberties and the rule of law, but I'll take partisan hostility in a pinch.