WASHINGTON » Even as they advocate for limited government, many of the Republican presidential candidates hold expansive views about the scope of the executive powers they would wield if elected — including the ability to authorize the targeted killing of U.S. citizens they deem threats and to launch military attacks without congressional permission.

As Republicans prepare to select their party’s 2012 presidential nominee, Newt Gingrich, Jon M. Huntsman Jr., Ron Paul, Rick Perry and Mitt Romney have provided detailed answers about their views on executive power in response to questions on the topic posed by The New York Times.

The answers show that most of them see the commander in chief as having the authority to lawfully take extraordinary actions if he decides doing so is necessary to protect national security. Only Paul, the libertarian-leaning congressman from Texas, argued for a more limited view of presidential power.

The views of the other four candidates who responded echoed in many respects expansive legal theories that were advanced by President George W. Bush. In certain significant ways, they dovetailed as well with the assertive posture taken by President Barack Obama since taking office, like his expanded use of drones to kill terrorism suspects — including a U.S. citizen.

The answers come against the backdrop of a decade of disputes over the scope and limits of presidential authority. Because executive branch actions are often secret and courts rarely have jurisdiction to review them, the views of the president — and the lawyers he appoints — about the powers the Constitution gives him are far more than an academic discussion.

Instead, in practice, a president’s views can influence such momentous matters as whether and how the country commits acts of warfare abroad, the rights of U.S. citizens at home and the ability of government officials to keep information secret from lawmakers, the courts and the public.

Asked to describe the circumstances under which the Constitution permits a president to order the targeted killing of a citizen who has not been sentenced to death by a court, Gingrich, Huntsman, Perry and Romney all said that a president could order the killing of a citizen who joins an enemy force that is at war with the United States, at least under certain conditions.

"My preference would be to capture, interrogate, and prosecute any U.S. citizen who has engaged in acts of war against the United States," Romney wrote. "But if necessary to defend the country, I would be willing to authorize the use of lethal force."

The Obama administration embraced similar reasoning as the basis for a drone strike in Yemen this year that killed Anwar al-Awlaki, an American whom executive branch officials accused of being a terrorist operative.

Paul, by contrast, described the circumstances in which a president could order the extrajudicial killing of a citizen in one word: "None." Similarly, while Paul said that a president should not order a military attack without congressional permission unless there was an imminent threat, the other four candidates agreed that a president could do so if he decided it was necessary.

An exception to that pattern was the use of signing statements to claim a right to bypass new statutes — often, provisions in bills that limit executive power — a president signs into law.

The three current and former governors among the candidates — Perry, Huntsman and Romney — each described circumstances in which he would use the device to raise constitutional concerns about legislation, with Romney outlining the most assertive version.

The two former House colleagues, Gingrich and Paul, said they would not issue such statements. (Gingrich has taken a more assertive view about constitutional disagreements with the judicial branch, saying presidents may lawfully ignore Supreme Court rulings.)

Two other Republican candidates, Michele Bachmann and Rick Santorum, did not answer the questions. Obama did not either; his re-election campaign said he had "pursued policies that strengthen our security" while "upholding our laws and values" and suggested that he would debate such matters in greater detail after Republicans chose his opponent.

Obama — along with Romney and Paul — participated in a similar project by The Boston Globe during the 2008 presidential primary campaign. His record in office shows how circumstances and the assumption of power can alter views expressed in a campaign.

Asked if a president could bomb Iran without congressional permission, Obama, then a senator, said, "The president does not have power under the Constitution to unilaterally authorize a military attack in a situation that does not involve stopping an actual or imminent threat to the nation."

In 2011, after the United Nations approved an air campaign in Libya to protect civilians, Obama — without congressional permission — deployed the U.S. military to join NATO allies in airborne attacks on Libyan government forces. In asserting the legality of that step, the Justice Department issued a memorandum saying that Obama had inherent constitutional power to do so because he could "reasonably determine that such use of force was in the national interest."

Later, Obama also adopted the view — overruling Justice Department and Pentagon lawyers — that he could lawfully continue the bombing and drone strikes beyond a 60-day clock imposed by the War Powers Resolution because they did not constitute the sort of "hostilities" regulated by that law.

In the survey answers, Perry criticized that approach, arguing that Obama should have instead asserted that the War Powers Resolution was an unconstitutional constraint on his wartime powers rather than employing "a convoluted, unbelievable definition of ‘hostilities.’ "

Presidential power has been growing since the early years of the Cold War and ratcheted forward under the Bush administration, which asserted sweeping theories of presidential powers to bypass statutory and treaty constraints, justifying a range of detention, interrogation and surveillance policies. As a candidate, Obama accused Bush of undermining the Constitution.

After taking office, Obama ordered strict adherence to anti-torture rules; justified his counterterrorism policies as authorized by Congress and consistent with international law, rather than invoking any inherent powers as commander in chief; and sought to handle terrorism cases that arise on domestic soil exclusively through the criminal justice system rather than using the military.

Still, Obama has outraged civil libertarians by keeping in place the outlines of many Bush-era policies, like indefinite detention and military commissions for terrorism suspects. And in the Libya air war and the targeted killing of Awlaki, he went beyond Bush’s executive-power record.

ON EXECUTIVE POWER

With the Iowa caucuses and the New Hampshire primary just days away, five Republican presidential contenders responded to a survey on executive power by The New York Times. Here are some of the candidates’ answers.

Q: Under what circumstances, if any, would the Constitution permit the president to authorize the targeted killing of a U.S. citizen who has not been sentenced to death by a court?

JON M. HUNTSMAN JR.: If such an individual is engaged on a battlefield it would be irresponsible not to kill him, just as the police often are forced to use deadly force in certain circumstances. The Fifth Amendment’s protection against the taking of life "without due process" does not mandate the use of judicial process in all circumstances; in the conduct of military operations, the relevant procedural protection is the executive branch’s commitment to taking all reasonable steps to ensure that the use of deadly force is warranted and necessary in the given case.

Q: Under what circumstances, if any, would the Constitution permit the president to imprison a U.S. citizen, arrested on U.S. soil, indefinitely and without charges as a military detainee?

NEWT GINGRICH: If such a person is waging unlawful combat against the U.S., the privilege of the writ of habeas has been suspended, or there is an imminent threat to the United States.

Q: In the absence of an imminent threat to the United States, under what circumstances, if any, would the Constitution permit the president to direct the armed forces to attack another country without receiving prior authorization from Congress? (Two examples to consider: a strategic bombing of a suspected nuclear site in a country like Iran, and a humanitarian intervention like the recent conflict in Libya.)

RICK PERRY: The Constitution clearly vests in the president full executive authority, and an absolute duty, to protect the nation when vital American security interests are at stake. There have been numerous examples where a president must direct our armed forces to engage even in the absence of an "imminent" threat. For example, during the Cuban missile crisis, when there was no imminent threat of missile launch, President Kennedy pre-emptively acted with a blockade against Cuba (an act of war) on the basis of the Monroe Doctrine and his power to defend the nation as our commander in chief.

Q: Under what circumstances, if any, would you sign a bill into law but also issue a signing statement reserving a constitutional right to bypass the law?

MITT ROMNEY: I share the view of many past presidents that signing statements are an important presidential practice in fulfilling the constitutional obligation to take care that the laws — which include the Constitution — are faithfully executed. I would follow their practice of using signing statements to set forth my understanding of ambiguous legal provisions or to protect presidential prerogatives established by the Constitution.

Q: The War Powers Resolution requires presidents to terminate deployments into hostilities that have not been authorized by Congress 60 days after notifying lawmakers that the campaign has begun; is that mandate constitutionally valid and legally binding on the commander in chief? Are air campaigns — that involve strikes on foreign adversaries but put U.S. forces at little risk — "hostilities" for purposes of that law?

RON PAUL: No. In fact, the War Powers Resolution, by allowing the president authority to unilaterally deploy troops for 60 days without congressional approval, gives too much unilateral war-making power to the president. Yes, bombing — and drone attacks — are acts of war.