PROVO — Brigham Young University students peppered U.S. Chief Justice John Roberts with questions Tuesday after he spoke before 7,080 people in the Marriott Center.

Roberts declined to answer hot-button questions about Guantanamo Bay detainees, gay marriage, Roe v. Wade, religion and political candidates such as Mitt Romney and some aspects of privacy law. He said judicial ethics forbade him from doing so because related cases may come before the court in the near future and because judges avoid political debates.

But other questions led Roberts to criticize the use of international precedent by some justices and to reveal his belief that technology-related cases could be the most important area of law considered by the Supreme Court over the next quarter of a century.

Just 52 years old and the youngest chief justice since 1801, Roberts is expected to preside over the court throughout that time.

Emerging technologies can create new questions about old laws. For example, imaging technology exists that allows law enforcement officers to see through walls. "Is that an unlimited search and seizure?" Roberts asked.

"People tend to be focused on what are the hot issues right now," he added. "Those are not the issues I think 25 years from now will be the ones people will look back on and say were significant."

Roberts strongly asserted his belief that U.S. judges should not use precedents established by international courts.

"When we look at domestic precedent, it narrows the authority of a judge," he said. "When we look at international precedent, it expands the authority of a judge. As one judge said, 'It's like looking out over a crowd and picking out your friends.'"

International relations major Evan Crockett asked Roberts about moral principles and whether the Supreme Court plays a role in foreign policy.

"I don't make moral decisions," Roberts said. "I make legal decisions. Sometimes, and even often, those legal decisions are contrary to the judgment I would make were it my job to shape policy, which is often guided by moral principles.

"Our constitutional decisions do have ramifications on foreign policies. That's not part of our job description ... but we are tasked to decide cases that involve the Constitution and involve both the granting authority in the area of foreign affairs to the president in some instances and to the legislature and also limitations on that."