Watching a Steven Spielberg movie is like riding in the back of an old Town Car. There’s plenty of room, the construction is solid, you know you’re heading somewhere, and even if there are bumps, the ride is always smooth. Indeed, Spielberg is so smooth, so good at what he does, that his best movies have a way of seeming inevitable, when they’re the furthest thing from it.

Case in point: "Bridge of Spies," which is the product of some thousand (or ten thousand) decisions that all happened to be right, from the casting, to the choice of shots, to the direction of the actors, to the costumes and art direction. There is a gift for story at work here, which is more than instinctive but has instinct at its core, that can be described but not fully explained. Every filmmaker takes you by the hand, but only some make you forget all about letting go — and they’re never the ones that grip the tightest.

The story of "Bridge of Spies" can be talked about in a number of ways, as a story about espionage or the Cold War, but at its heart it’s a character portrait.

Specifically, it’s the story of a man of principle who, when confronted by the biggest drama of his life, got bigger instead of smaller. James B. Donovan, a New York lawyer in the 1950s, is played by Tom Hanks, who is the acting equivalent of Spielberg. He doesn’t do anything fancy. He just does the right thing from moment to moment, with his uncanny way of always knowing what the right thing is.

The movie begins with what could almost be a silent sequence, in which we encounter Rudolf Abel (Mark Rylance), a whimsical, unassuming man who is soon revealed to be a Soviet spy. These early scenes are set in New York in 1957, and you could hope for no better transport to an earlier era outside a time machine. It’s not just the cars and the costumes that are perfect, but the fonts on the signs, and the kinds of businesses shown on the street, not to mention a bridge in the distance that looks newer than it does now, and the use of film stock that evokes a Technicolor newsreel.

When we first meet Donovan, he is negotiating on behalf of a client in his capacity as an insurance lawyer.

We notice two things right away: He knows how to win, even while negotiating from a weak position. He can argue vigorously, while alienating no one. These abilities will come into play later in the film.

History finds Donovan, and the movie kicks into gear, when he is enlisted to defend Abel, who is accused of espionage. The American government wants Abel to have a good lawyer to demonstrate to the world that Abel is being treated fairly. What they don’t expect is for Donovan to mount an actual defense. Some of the best scenes involve Donovan’s clashes with the presiding judge, played by Dakin Matthews, who assumes a superior air, even as his manner suggests the unease of a proud man taking orders from upstairs.

"BRIDGE OF SPIES" Rated: PG-13 Opens today

Spielberg and the screenwriters (Matt Charman and Ethan and Joel Coen) present Donovan as a kind of ideal combination of geniality and perception. Before anyone, he has the notion that a foreign spy should be treated differently from a domestic traitor, bearing in mind that America has spies working in other countries, as well. This becomes important as "Bridge of Spies" transmutes from the story of a court case into one involving the shoot-down and crash of U-2 pilot Francis Gary Powers.

Spielberg being Spielberg, the scene in which the U-2 is shot down, from an altitude of 70,000 feet, is harrowing in its execution.

But then all the details of this film feel right, whether it’s the glazed look of people on a New York subway, or the soul-sick frenzy of Berlin just as the wall was going up. Spielberg throws away nothing, so that a single scene involving CIA Director Allen Dulles isn’t merely functional, but has reverberations to it. Without seeming to be doing much in particular, actor Peter McRobbie makes you think that everything you’ve ever heard about Dulles is true, especially the bad things.

In the end, most movies about history are in some way about the times in which they were made. "Bridge of Spies" is not a direct allegory for our times, but rather a useful reminder that at all the pressure points of our history, there have always been people ready to do an end run around the U.S. Constitution, either out of fear or convenience. "Bridge of Spies" tells us that the Constitution is not some quaint national luxury but the road map out of the darkness.

Review by Mick LaSalle, San Francisco Chronicle