By Paul Reidinger

THE DINER MAY be an American institution – the word diner is redolent of fluorescent bonhomie, and it served as the title of Barry Levinson's memorable 1982 film, with its many scenes of fluorescent bonhomie – but as the country has changed, so too have its institutions, for better and worse. For examples of worsening, of course, we need look no further than to the ongoing political antics in Washington, D.C., a city of marble colonnades in which Congress slumbers, the Supreme Court schemes, and the president is continually reaching for his six-shooter while hungry hawks circle overhead. America's proudest institutions have always been political, legal, and governmental, yet one notices that not a single nation to emerge in the world since World War II – an interval, not coincidentally, of constant American preparedness for war – has adopted our form of governance. If imitation is the sincerest form of flattery, what then are we to make of our apparent inimitability – and why do we never mention it?

But enough bad news. The good news is that some American institutions have improved, among them the iconic diner. For an example of the latter, we turn to Mission Bar and Grill, which opened not quite two months ago under the auspices of onetime Val 21 proprietors Nidal and Saandra Nazzal. If you remember Val 21, you will immediately pick up familiar design cues at the new place, among them the forest green paint scheme (paired with stretches of rosewood paneling) and the modish, art deco-style lamps suspended over the bar. But MB&G strikes its own notes too, from the subtle (checkerboard floor tiles) to the obvious (the sunburst mirror opposite the bar). It is also much cozier than Val 21, and less noisy.

The food reflects a number of trends. The menu is tight, consisting of a single page of openers and salads, small plates, and larger plates. Only one or two items cost more than $10. But it is the ethnic mixing, or layering, that most sharply captures the attention: MB&G is an (American) diner owned by people of Middle Eastern origin set in a predominantly Latin American, and economically diverse, neighborhood.

So it makes a kind of sense very much of our time and place that the menu would offer a Mediterranean plate ($6.95) – mainly paprika-sprinkled hummus and tabbouleh, with pitted black olives, cherry tomatoes, and warm, tender pita triangles on the side – and a plump mushroom quesadilla ($3.50) fanned about a red mound of salsa, and a cheese steak sandwich ($7.95) with top-tier fries.

At the same time the cooking honors (as it did at Val 21) the California principle of vivid simplicity. A grilled portobello mushroom ($6.50), lightly caramelized at the edges, arrives embedded in mixed greens; it seems like an ordinary dish, except that the greens are voluptuously dressed with a fruity vinaigrette. An albacore tuna sandwich ($6.50) carries a good puckering charge of capers. And spicy crab cakes ($6.95), a local staple, are made simultaneously more handsome and a bit richer by pipings of aioli.

Although MB&G, with its cool tiles and signage illuminated by curvaceous red lamps, looks to be on the swank side relative to its setting – Mission Street in the 20s isn't exactly the Boulevard St. Germain, and the other swank restaurant nearby, Foreign Cinema, is almost invisible from the street, like an exclusive nightclub, or a fortress – you get a lot for your money. We watched two fairly immense platters of food (pasta in a bolognese sauce, and a grilled pork chop) arrive at the table next to ours even as we were working our way through a skirt steak ($9.95), grilled to a juicy medium rare and cosseted by heaps of Spanish rice, pinto beans, and salsa, with warm tortillas on the side. The idea seems to be to attract the neighborhood's upmarket diners while not scaring everybody else away, and the big hurdle there might be convincing people who don't have tons of money to spend that they can afford to eat in a place as good-looking as Mission Bar and Grill.