Washington (CNN) In the wild and whirling age of Donald Trump, President Barack Obama went for stable, sober and conventional.

Obama's pick of Judge Merrick Garland for the vacant Supreme Court seat Wednesday was an intriguing multi-layered move in his last great showdown with Republicans that comes at a time of volatile political upheaval.

His selection demonstrates cold-eyed calculation and represents a clear case of Obama calling the Republicans' bluff after its leaders made clear they would refuse to consider his nominee whomever it turned out to be.

Garland's elevation offers a new window into the state of Obama's political philosophy in the twilight of a presidency that began in a burst of historic potential but has been constrained by the grueling struggle to govern in a polarized era.

The pick, a mild surprise, also seemed to hold up a mirror to the President's nature. Obama billed himself as the picture of swashbuckling audacity at the beginning of his career but has often proven to be too centrist from some liberals' tastes on issue from health care to anti-terrorism policy.

Rarely immune to the lofty gesture, Obama also aimed to make a profound statement about America's political institutions and democracy itself at a time when a vicious election campaign distilled from years of raging partisan heat is tearing at them.

Though he did not mention Republican presidential front-runner Trump by name, Obama's point was hardly subtle. The President argued that while the rules of politics in a rabble-rousing moment might be fraying, some things -- like the nomination of a Supreme Court justice --- are so vital that they should be above the partisan swamp.

"At a time when our politics are so polarized, at a time when norms and customs of political rhetoric and courtesy and comity are so often treated like they're disposable -- this is precisely the time when we should play it straight," he said.

"Because our Supreme Court really is unique. It's supposed to be above politics. It has to be. And it should stay that way," said a President who once called out the justices in person over the Citizens United ruling on campaign finance during a State of the Union address.

"To suggest that someone as qualified and respected as Merrick Garland doesn't even deserve a hearing, let alone an up-or-down vote, to join an institution as important as our Supreme Court," Obama said, "that would be unprecedented."

Calling the Senate's bluff

Obama has admitted that he has sometimes fallen short on the theatrics of the presidency.

But he did not shirk on the stage management Tuesday, as he shepherded Garland into the spring-filled beauty of the White House Rose Garden, the venue for many symbolic and ceremonial presidential moments over the decades.

The President's appearance validated one of the great truths of Washington -- that when someone professes to be above the grubby political impulses of his rivals, he's usually playing the game at a more sophisticated level himself.

In essence, Obama was signaling to the GOP that whatever political price there is to pay for their refusal to consider his pick, the bill is now due.

"In this sense, then, the President is calling the Republican Senate's bluff," said Professor Thomas Keck, an expert on the Supreme Court and U.S. politics at Syracuse University.

"If the Senate's leaders stick to their pledge not to consider or even meet with any Obama nominee, it will be clear that they are doing so solely for partisan reasons and not due to any concerns with the nominee's qualifications or record."

There was also another implicit political message for Republicans to digest. Obama could have chosen a more liberal, Democratic-base-pleasing nominee in election year, but didn't, disappointing some on the left of his party.

In the context of a campaign that could produce a mandate for a Democratic successor, Hillary Clinton, who has been dragged left by her own party, he seemed to be saying to Republican senators: take what I am offering or you may rue the day.

"President Obama is saying to the Senate Republicans, you can take my 63-year-old now or wait for President Hillary Clinton to bring up a 45-year-old in 10 months," said CNN Senior Legal Analyst Jeffrey Toobin.

Garland, the man for the time and place

In many ways, Garland is a case of cometh the political hour, cometh the man.

He has been passed over for previous spots on the court as apparently insufficiently 'historic' or youthful, as Obama picked the first Hispanic on the bench in Sonia Sotomayor and then Elena Kagan, who could have decades left to exert his progressive legal outlook.

But the spectacularly conventional nature of Garland's resume — from Harvard Law to distinguished and unblemished service in the Justice Department to the top appeals court in the land -- that worked against him before suddenly became an asset.

So while Sotomayor satisfied his impulse to make history, his later picks of Kagan, his former solicitor general, and especially Garland show a streak of pragmatism often evident during his presidency.

A President hoping to make Republicans look bad for blocking his appointment could hardly have found anyone so objectively qualified to serve.

It didn't hurt either that Garland had previously been confirmed by several sitting Republican senators when he was nominated by President Bill Clinton, who the senators spoke of him in glowing terms.

The picture of unquestioned merit was solidified when Garland took to the microphone in the Rose Garden. His voice cracked as he spoke of the "gift" of his nomination and his love for his family, his nation and the Constitution, coming across as the modest and personable antithesis of the scheming, agenda-driven vortex into which he had just stepped.

And now, the Senate battle

Contrasting with Obama's theatrics, Senate Majority Leader Mitch McConnell, in his unspectacular style, put on a show of quiet defiance to stiffen the spine of his troops in swing state re-election contests who may not relish the fight ahead.

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"It is a president's constitutional right to nominate a Supreme Court justice and it is the Senate's constitutional right to act as a check on a president and withhold its consent," McConnell said in his flat monotone, like a lawyer stating the facts of a case.

And McConnell, speaking from the Senate floor, showed the President that two can play the political game, reviving an old quote from Vice President Joe Biden.

"'It would be our pragmatic conclusion that once the political season is under way, and it is, action on a Supreme Court nomination must be put off until after the election campaign is over,'" McConnell quoted his old Senate sparring partner saying in 1992.

Republicans trawling for White House hypocrisy might have also taken exception to Obama's Rose Garden announcement itself -- since Biden -- a key player in obstructionist Supreme Court confirmation fights in the past, including his orchestration of the rejection of President Ronald Reagan pick Judge Robert Bork -- stood alongside the President as he made his speech.

In some ways, Garland's nomination is a poisoned chalice: it is highly likely that he won't get a hearing and his chances of claiming late Justice Antonin Scalia's seat are questionable at best. There is no guarantee, for instance, that Hillary Clinton, if elected president, would renew his nomination, given pressure on her to demonstrate early progressive credentials by appointing a more clear-cut liberal.

That was why Garland's comments about his nomination being "the greatest honor" of his life other than his marriage and the "greatest gift" other than the birth of his daughters were so striking.

They seemed to hint that even if he does not make it to the bench, Garland may view the fact that he was chosen at all as no small honor. Or he could be a man for whom the prize of the high court is so great that it is worth braving the political fire to come.

If Garland's nomination does fail, he can go back to his job as top judge of America's second-most prestigious bench -- the United States Court of Appeals for the District of Columbia Circuit.

Thus, Obama will not have torched a less established judicial career, or burned a potential Supreme Court nominee likely to excite liberal ideologues, like Garland's colleague Sri Srinivasan, who a future Democratic president may wish to put forward.

And while Washington seems resigned to a stalemate in which Garland is left in unconfirmable limbo, the White House may still hope that things could change.

Should November's election produces a President Clinton -- or even the upredictable ideological prospect of a President Trump -- some GOP senators could be tempted to cut their losses in a lame duck session of Congress and settle for the judge they know.