The biggest exception to their conservative outcomes came on LGBT rights, when Gorsuch wrote the court's 6-3 decision interpreting Title VII of the 1964 Civil Rights Act as barring discrimination based on sexual orientation and gender identity.
"Gorsuch stuck to his textualism commitments to reach a result that conservatives did not like," said Gillian Metzger, a constitutional law professor at Columbia Law School. "But you're not going to get conservative or liberal justices voting in lockstep in every case."
Gorsuch also joined the liberals in a 5-4 ruling that said much of eastern Oklahoma, including Tulsa, remains American Indian territory. He said the federal government had promised the land to the Creek Nation in two treaties in the 1830s.
"Because Congress has not said otherwise, we hold the government to its word," Gorsuch wrote. The ruling raises questions about Oklahoma's power to prosecute Native Americans and enforce regulations. Kavanaugh dissented.
Unlike Gorsuch, Kavanaugh didn't cast the pivotal vote to join the liberals in any 5-4 majority this term, according to Adam Feldman, creator of empiricalscotus.com, which tracks Supreme Court trends.
Like Roberts, Kavanaugh tends to prefer narrow rulings, and he agreed with Roberts more than any other justice, according to Feldman's statistics. But Kavanaugh joined Roberts and the liberals only twice in 6-3 majorities in argued cases, including a clash over the scope of the Clean Water Act.
"There was some thought, when Justice Kavanaugh joined the court, that he would provide cover for the chief justice by joining the chief when he did something that disappointed conservatives," said David Strauss, a constitutional law professor at the University of Chicago Law School. "But that hasn't really happened."
In the marquee cases of the term, the fights over Trump's financial records, Kavanaugh and Gorsuch voted with Roberts and the liberals to reject the president's bid for a sweeping shield from state grand jury investigations.
But even there, the two added a pro-presidential spin. Rather than join Roberts' majority opinion, Kavanaugh wrote separately to say state grand juries should have to show a "demonstrated, specific need" for presidential records -- a tough standard the chief justice chose not to apply. Gorsuch joined Kavanaugh's opinion.
In argued cases alone, the court issued nine 5-4 opinions with the five Republican-appointed justices -- Gorsuch, Kavanaugh, Roberts, Clarence Thomas and Samuel Alito -- in the majority, Feldman said. That doesn't include a significant number of emergency applications that divided the court along ideological lines.