U.S. Supreme Court Chief Justice John Roberts said Wednesday he thinks rapidly advancing technology poses one of the biggest challenges for the high court.

Speaking at an event at the Victoria University of Wellington in New Zealand, Roberts also repeated his concern that the confirmation process for Supreme Court justices has become too politicized. And he advised that having a written constitution, which some in New Zealand favor for their country, imposed constraints on judges.

Roberts answered questions posed by the university’s law dean, Mark Hickford, for about an hour.

Hickford did not ask any questions about U.S. President Donald Trump, who has criticized judges including Roberts and imposed a travel ban on people from six mostly Muslim countries that has been challenged in the courts.

The Supreme Court said last week the Trump administration can enforce a ban on refugees but also left in place a weakened travel ban that allows more relatives of Americans to visit.

At the New Zealand event, Roberts said technology was a real concern.

“There are devices now that can allow law enforcement to see through walls. Heat imaging and all this kind of thing,” he said. “Well, what does that do to a body of law that’s developed from common law days in England about when you can search a house?”

He said the court had correctly determined that accessing an iPhone was problematic under the constitution’s Fourth Amendment.

“I’ll say it here: would you rather have law enforcement rummaging through your desk drawer at home, or rummaging through your iPhone?” Roberts said. “I mean, there’s much more private information on the iPhone than in most desk drawers.”

He said none of the Supreme Court justices are experts in the area and it is going to be a particular challenge for them to make sure they understand the issues and for lawyers to explain them.

Asked about the benefits of a written constitution, Roberts said he didn’t want to offer advice to New Zealand but that the U.S. Constitution had a constraining purpose and affect.

“The framers of the constitution hoped they were drafting a document that would withstand the test of time, and they used, in many instances, very broad and capacious terms,” he said. “But on the other hand, they can be specific guides as to what we are supposed to look at, and in some cases quite narrowly confining.”

New Zealand’s constitution is not contained in any one document but is derived from laws, legal documents, court decisions and conventions.

Roberts said the U.S. judicial process has become overly politicized, particularly when it comes to the confirmation of Supreme Court justices.

“Judges are not politicians, and they shouldn’t be scrutinized as if they were,” he said. “You’re not electing a representative, so you’re not entitled to know what their views on political issues are.”

(AP)