WASHINGTON – After 15 years on the bench, Chief Justice John Roberts has emerged to be what many legal experts describe as the most influential head of the Supreme Court since the 1940s.

With two of its nine members appointed by President Donald Trump, the conservative-dominated court was thought by many to be drifting far to the right and threatening to undo progressive social policies.

Instead, during its 2019-2020 term, which concluded last week, the court under Roberts defied Trump and his conservative allies in a string of cases, casting a light on the otherwise conservative chief justice’s inclination and ability to achieve consensus.

These opinions struck down a Louisiana abortion law, expanded protections for LGBTQ people, and kept intact a government program for young undocumented immigrants. In two other cases on the final day of the court’s term, the justices rejected Trump’s claims of immunity from subpoena for his financial records.

At the center of it all was Roberts, 65, who was appointed by former Republican President George W. Bush in 2005. Roberts not only wrote several of the landmark opinions but was able to persuade one or both of Trump’s conservative nominees — Neil Gorsuch and Brett Kavanaugh — to join the more liberal justices.

Of particular significance was the frequency with which Roberts voted with the majority, a measure of his growing influence and willingness to play the role of consensus builder.  In all but two of the 58 cases heard by the court, Roberts was in the majority.  That is something no other chief justice has achieved since Harlan F. Stone, who headed the court from 1941 to 1946, according to Adam Feldman, creator and author of the Empirical SCOTUS Blog.

“Influence is such a subjective measure that without access to the justices’ conferences, it is very difficult to gauge. But with all the material at our disposal, he does seem to be the most powerful justice since Stone,” Feldman said.

Others, such as Harvard Law professor Noah Feldman, have gone much further, comparing Roberts to John Marshall, the legendary and highly influential fourth Chief Justice of the United States, who presided over the court from 1801 to 1835.

For an otherwise low-key chief justice, the comparisons are surprising.  A graduate of Harvard Law School, Roberts worked in the Department of Justice and the Office of the White House Counsel in the 1980s and 1990s. In 2005, after a two-year stint on the powerful U.S. Court of Appeals for the District of Columbia Circuit, Roberts was nominated by Bush as an associate justice of the high court. However, before his confirmation hearing was held, then-Chief Justice William Rehnquist died, and Bush renominated Roberts for the top job.

Swing vote

For most of Roberts’ tenure as head of the divided bench, retired justice Anthony Kennedy, another Republican appointee, was the “swing” member of the court, casting the decisive vote in a string of landmark cases that upheld abortion rights and legalized gay marriage, among other issues.

With Kennedy’s retirement in 2018, Trump nominated Kavanaugh as Kennedy’s replacement, effectively pushing the more moderate Roberts to the ideological center of the court. That has given him unparalleled influence, enabling him not only to swing the court but also to write many of the opinions for the big cases himself.

In two of three major cases — a ruling against the Trump administration’s effort to end the Deferred Action for Childhood Arrivals (DACA) program and an opinion striking down a Louisiana abortion law — Roberts cast the decisive fifth vote. He wrote the majority opinion in the DACA case.

In the third case, in which the court determined employers cannot discriminate against LGBTQ people, both Roberts and Gorsuch joined the majority. Gorsuch wrote the opinion in that case.

The decisions drew the ire of Trump, who blasted them as “horrible and politically charged” and indicated that — much as in 2016 — he would  elevate judicial appointments into a campaign issue this year.

“We need more Justices or we will lose our 2nd. Amendment & everything else. Vote Trump 2020!” Trump tweeted after the DACA ruling.

Center of conflict

This is not the first time Roberts has found himself in conservatives’ crosshairs. In 2012, he upset many on the right when he joined the liberal wing of the court in upholding the constitutionality of the Affordable Care Act, then-President Barack Obama’s signature health plan for the uninsured, colloquially known as Obamacare.

But with so many decisions going against them this term, conservatives have never been more furious with the chief justice.

“This term was probably the worst from a conservative point of view, worst from a principled point of view,” said Curt Levey, president of the conservative Committee for Justice.

While some conservatives worry that the court will likely drift further to the left with Roberts at the top, Levey said, “the best we can hope for from a conservative point of view at this point is a moderate court with Roberts as the swing vote, keeping our fingers crossed that he doesn’t go full Souter.”

David Souter, a Republican-appointed justice who served on the Supreme Court from 1990 to 2009, gained notoriety among conservatives for his proclivity to vote with the liberal wing.

But Roberts is not Souter. On most conservative issues, he consistently votes with his ideological cohorts. He has joined more 5-4 conservative opinions this term than he did last term. In three religious liberty cases, he joined the majority in favor of religious organizations.

Yet on hot-button issues like abortion rights, he has parted ways with the more conservative justices, in part, legal experts say, to avoid the perception that the justices often vote along party lines.

These “strategic” votes are designed to achieve a particular outcome in the face of public pressure, Levey said.

But liberal activists say Roberts’ votes do not make him any less conservative than his ideological associates on the court.

“There is no question that Roberts has disappointed conservatives who expect him to ignore the law no matter the case and simply deliver ideological victories in lockstep with the right,” said Elizabeth Wydra, president of the liberal Constitutional Accountability Center. “The fact that Roberts is now sometimes a ‘swing’ vote on this court only shows how conservative the court as a whole really is.”

At a time when Supreme Court justices are seen by some as “politicians in robes,” experts say Roberts remains deeply concerned about the court’s institutional legitimacy, willing to go to great lengths to defend its reputation.

Last year, when Trump disparaged a federal judge who had ruled against him as an “Obama judge,” Roberts issued an extraordinary rebuttal.

“We do not have Obama judges and Trump judges, Bush judges or Clinton judges,” Roberts said in a statement.

Yet a determination to defend the court’s reputation is not all that is driving Roberts’ decision-making, experts say. Roberts is a judicial “minimalist” whose decisions are guided by a desire to avoid disruptions, according to Jonathan Adler, a professor of law at Case Western Reserve University and editor of a book on the Roberts court.

“He does not make decisions that disrupt settled expectations or that dramatically overturn precedents or produce big changes,” Adler said. “He prefers decisions that are relatively minor and narrow.”

Case in point: In striking down the Louisiana abortion law, Roberts wrote that he felt compelled to follow precedent set by a similar case four years ago, even though he disagreed with it, Adler noted.

“The question today, however, is not whether (the 2016 case) was right or wrong, but whether to adhere to it in deciding the present case,” Roberts wrote in a concurring opinion.

Another example: Roberts joined the court’s four other conservative justices to declare the leadership structure of the Consumer Finance Protection Bureau as unconstitutional, but he stopped short of invalidating the agency.

This kind of narrow ruling has the effect of generating broader consensus, Adler said.

“He places a value on there being stability and clarity in the law, and he places a higher value on that than necessarily on reaching what he would think would be the doctrinally pure outcome,” Adler said. “That is certainly a way in which he differs from the other conservative justices on the court.”