Again I think you're right. Bear with me on what follows.
Marbury v. Madison may be my favorite Supreme Court case because while it's seminally huge, it's also blatantly political and politically brilliant. At the risk of boring you and others, the case arose out of the Federalists' frantic efforts to maintain control over the federal government after an electoral tidal wave that elected Thomas Jefferson and would effectively kill what we would now think of as the Federalist Party.
As Jefferson's inauguration approached, the Federalists -- specifically including John Adams' then Secretary of State John Marshall -- were frantically signing "commissions" that would empower loyal Federalists to take positions in what would become a Jeffersonian administration. Riders galloped literally into the night to deliver these “midnight commissions”, in a rearguard action to maintain Federalist influence. As it happened, a commission for William Marbury didn't arrive in time, and President Jefferson's Secretary of State, James Madison, refused to honor it. Marbury sued Madison to become a Justice of the Peace, as promised by Marshall's belatedly delivered commission. Hence Marbury v. Madison.
In the short time it took for Marbury's case to reach the Supreme Court, John Marshall had graduated to Chief Justice through the very sort of finagling that had produced the Midnight Commissions that he himself had signed and as to which he would now adjudge. This was, to put it politely, a complicated scenario.
To step back a moment, Marshall wasn't merely a partisan Federalist -- although he surely was that -- he was deeply committed to the idea of a strong federal government. And he believed that without a strong Supreme Court the federal government wouldn't be supreme over the various state governments.
Meanwhile, the fledgling Supreme Court didn't have anything like the clout it possesses today. It really was "the weakest branch", and Supreme Court appointees often declined or never showed up, because the Court was then thought of as an afterthought, and the duties of the then Justices were ignoble, embarrassing, hard, and unappreciated.
Meanwhile there was a huge Jeffersonian blowback at extraordinary Federalist abuses like the Alien and Sedition Acts, which made it a federal crime to say mean things about John Adams and as a result of which Jeffersonian newspaper publishers were sometimes imprisoned. (These Acts were never officially struck down, but no one doubts that they were unconstitutional.) This blowback led to impeachment drives against Federalist judges, some of which were successful, and Marshall understood full well that a target was on his back.
If Marshall granted relief to William Marbury (whose commission he had signed) a furious and vengeful President Jefferson would ignore his decision, Congress would impeach him, and the judiciary might become a merely vestigial branch of the federal government. If he declined Marbury's petition, he'd have to renounce his own actions. So he did neither.
In the first section of the Marbury opinion, Marshall excoriated the Jefferson administration for lawlessly denying Marbury his lawful job. In the second section, Marshall held that the Judiciary Act of 1789 unequivocally granted the federal courts power to right this heinous wrong. But in the third section – and this is where it all happens – Marshall held that the 1789 Judiciary Act was unconstitutional, because it gave the Supreme Court too much power. As a result, Marshall held, he had no choice but to dismiss Marbury’s claim, because the statute under which he’d filed it was unconstitutional.
Look at what just happened here. In the guise of quiescently abdicating the authority to grant Marbury relief, Marshall has just struck down a federal statute as unconstitutional. (It had never happened before and wouldn’t happen again for decades.) While I think the Supreme Court absolutely has the authority to do this, there isn’t a single provision of the Constitution that expressly says so, and Marshall knew it. While encouraging everyone to focus on the politics of his decision, he distracted attention from his decision’s huge judicial consequences.
I say all of this because John Roberts has read Marbury and may be doing exactly what you suggest.