During a hearing Tuesday on President Trump’s travel ban, Ninth Circuit Judge Michelle Friedland asked a question.

Was the Trump administration arguing that the president could do what he wanted on national security matters and the courts had no authority to step in?

The lawyer representing the Justice Department paused, and then answered: “Yes.”

The answer was shocking to some legal watchers: Since Marbury v. Madison in 1803, the judiciary has served as the ultimate arbiter of the law and a check on the other branches of government.

But in other ways, the answer was simply stating the reality of much of the past century. Until recently, the courts have deferred when asked to check the steadily expanding power of the executive branch. That was a matter for the president to work out with Congress, the legal thinking went.

But now there are signs that the judiciary may be increasingly willing to pull back on the reins – at least a bit. And regardless of whether Mr. Trump’s individual executive order is upheld or not, the high-profile legal battles over it seem to be drawing more public – and judicial – attention to how executive power has expanded, and its potential consequences.

“We need to be aware that the decisions the courts are making, and the assertions the Trump administration is making in these cases, are going to apply not only to these cases but to assertions of executive authority in the future,” says Steven Schwinn, an associate professor at the John Marshall Law School in Chicago.

The growing willingness to scrutinize executive power can be traced at least partly to the recent rise in legal challenges, experts say. As George W. Bush and Barack Obama pushed the limits of executive authority, legal pushback has grown.

“The Supreme Court has reined in the more extreme claims of executive authority that we have seen in the last two presidential administrations,” says Professor Schwinn.

There was widespread litigation, particularly from civil liberties groups, over many of Mr. Bush’s actions responding to the 9/11 attacks, and Republican state attorneys general systematically challenged many of Mr. Obama’s executive actions.

Now Trump is issuing a flurry of his own executive orders, including the one currently before a panel of the Ninth Circuit. It bars citizens of seven Muslim-majority countries from entering the United States for 90 days. It also prevents entry for all refugees for 120 days and indefinitely halts the admission of Syrian refugees.

The Ninth Circuit is considering whether to uphold a federal judge’s decision to block the order. Its ruling is expected within days, and the case is considered likely to end up at the US Supreme Court. In a sign of the keen public interest, more than 2.6 million people listened to the hearing, which was streamed live.

Roots of executive power

The Constitution doesn’t actually endow the president with much unilateral authority. Coming out of a monarchy and wary of concentrating power in an individual, the Framers granted the president only one independent power: the ability to issue pardons and reprieves.

“Obviously that has changed significantly over time,” says Mark Rozell, dean of the Schar School of Policy and Government at George Mason University and an expert on presidential power.

Most scholars trace this expansion to Franklin Roosevelt, who entered the White House at the nadir of the Great Depression and launched an aggressive, executive-driven agenda to revive the country. His flurry of actions during his first 100 days in office transformed Americans’ views and expectations of what the president should do.

There is now an “underlying assumption” that a president should do as President Roosevelt did, says Dr. Rozell, author of “Executive Privilege: Presidential Power, Secrecy, and Accountability.”

Specifically, a president is expected to come in “with a bold vision, an activist agenda, and a plan to bulldoze it through Congress,” he adds.

There may be valid reasons for broadening executive powers, says Ernest Young, a constitutional law professor at Duke University School of Law.

The executive branch is inherently the most nimble branch, and can respond quickest to crises and emergencies. As the branch has grown, it has also accrued more expertise on subjects from housing and water quality to space travel and terrorism.

Courts and Congress have been enablers

But presidents haven’t been the only ones to expand executive powers. Most of presidents’ current powers have been delegated by Congress and upheld by the federal court system.

Part of Trump’s justification for his order, for example, is that the 1965 Immigration and Nationality Act, passed by Congress, gives him the power to suspend the entry of “any class of aliens” into the US if it “would be detrimental to the interests of the United States.” (Opponents disagree with this interpretation.)

Congress has also enacted laws giving the president broad discretion in war, national security, and foreign policy. The legislature has also expanded the executive branch itself, creating agencies like the Environmental Protection Agency (in 1970) and the Department of Homeland Security (in 2002).

The court system has largely played along. Part of this stems from the judiciary’s fundamental role in government – to not be a rulemaking body, but to assess the legality of rules enacted by Congress and the president. Yet the judicial branch has also arguably facilitated the decades-long expansion of executive power.

The Chevron doctrine, for example, originates from a 1984 Supreme Court case. It holds that, if Congress passes an ambiguous law, the executive branch regulatory agencies should be able to interpret those laws – unless the agencies’ interpretations are unreasonable.

Meanwhile, for the past 80 years, the high court has essentially ignored the doctrine that there are constitutional limits – to be determined by the judiciary – on the legislative powers that Congress can delegate to the executive. Since 1935, the court has never found a delegation of power by Congress to the executive unconstitutional.

Essentially, the court “has been upholding any and all delegations of power to the president” since 1935, says Professor Young.

A shift in thinking

But the increased attention has seen the courts begin to check executive power a bit more.

“I’m not sure the courts are interested in particular in reining in executive power, but I do think [they] are taking a closer look at these cases,” says Schwinn.

Furthermore, a number of judges and scholars – including Neil Gorsuch, Trump’s nominee to the Supreme Court – have become increasingly critical of the Chevron doctrine. While that doctrine is unlikely to come up in any travel ban litigation, it is another sign that the judicial tide could be turning against the expansion of executive power.

For now, Trump’s executive orders appear to be drawing even more public attention – and judicial scrutiny – to how executive power has expanded.

“Sometimes those delegations [of power] are made on the assumption that this power is never going to be exercised by someone who you’d worry what they’d use it for,” says Young.

“I would love to see one legacy of this be that Congress takes a look at some of these very broad delegations and narrows them.”