Keep it simple. That's perhaps the most important thought to bear in mind as the process begins in earnest to redesign the empty area in front of the White House that was once bustling Pennsylvania Avenue.

There are other key slogans: Make haste slowly. Remember the Avenue. Remember the White House, and the city. This is an opportunity, not a problem.

But keeping it simple is guide No. 1. It is an antidote to the hysteria of big ideas that broke out after the avenue was suddenly closed for security reasons in May. Obliterate the avenue, some suggested, by expanding Lafayette Park. Or make the space a memorial to this person or that cause. Or launch a national design competition.

Six weeks later, it's clear that the open space in front of the president's house is an inappropriate location for experimentation on a grand scale. The starting point of any design is to pay close attention to what already is there: a house, a park and a street. These three parts need to be tied together in an elegant composition. That's the job.

Of course, simple doesn't necessarily mean easy. Some hard, basic decisions have to be made before a designer can get on with the job. And simple does not imply that the new design would lack richness, subtlety and strength. To the contrary, these qualities are the goal.

Keeping it simple means that we shouldn't jump through hoops we don't have to jump through. An open design competition is one of these unnecessary hoops. It might produce the desired result. But more likely, it would create controversy and confusion, and gum up the works for months, possibly years.

The idea of such a competition has a certain surface appeal. It sounds so democratic and fair. Yet a competition is inherently chancy. The most qualified talents often don't enter for fear of losing or wasting time. And a lot depends on the jury -- there's no certainty that the most appropriate design will win. Then you're stuck with the winner, and all sorts of complications ensue.

Most important, an open competition encourages just the sort of high-flying originality that is not wanted here. Architects, landscape architects and artists are naturally enticed, and often led astray, by the challenge of starting over, of treating even hallowed ground as a blank slate.

This is the opposite of what's needed in front of the nation's primary residence. Which brings to mind the other mottoes for this endeavor. Let's take them in order.

Make haste, slowly. The president, according to White House Chief of Staff Leon Panetta, has asked that a "long-term design" be "completed and constructed" by the next inauguration. He also requested that an "interim beautification" -- that is, a tidying of the ugly mess created by those Jersey barriers -- be in place by this September.

Leaving aside the short-term goal, the question is: Can it be done in 19 months? Only if everything were to fall perfectly into place. This is highly improbable -- impossible, if there's an open competition. (You have to make the rules, publish them widely and allow competitors a reasonable time -- six months, say -- to enter. Then comes the judging, and then the mandatory federal and local reviews.)

And should it be done in such a rush? Probably not. True, you don't want this project to get lost in the Washington shuffle. Landscape architect Joseph Brown has had plenty of experience with the government design system; with colleagues at the national firm EDAW, he designed the Signers' Memorial in Constitution Gardens. He says he has "an allergic reaction to taking longer in Washington, because longer means maybe never, or it means 10 or 12 years." But it's a mistake to push too hard. January 1997 may be a politically compelling date, but in terms of design, it's arbitrary.

This should be kept in mind, especially by the White House, for today's decisions will affect the city for generations. It's encouraging that responsibility has been turned over to the National Park Service. For one thing its director, Roger Kennedy, is a design-sensitive bureaucrat. And for the past three years, the Park Service has been leading a multi-agency study of the White House area. This new mandate fits right in -- except for the extraordinary time pressure: Kennedy was told to come up with cost estimates and so forth by mid-July.

Decisions need to be made fast, but not too fast. They must be the right decisions. Of course these are judgment calls, and judgments will differ. But the site itself offers strong guidance -- which is why we say: Remember the Avenue.

Two fundamentally different approaches to Pennsylvania Avenue emerged immediately after the Treasury Department closed the street on May 20. Drawings released at the time showed the opposite treatments. One (by Mark Bunnell) literally eliminated the section of the avenue by extending southward the trees and curving walkways of Lafayette Square. The other (by John Carl Warnecke, who had initially proposed closing this section of the avenue more than three decades ago, during the Kennedy administration) showed a sort of residual boulevard, with fountains and formal plantings in the middle.

Fortunately, there's not much -- if any -- question about which is the right way to go. Keeping the street, in some form, must be the first principle of any design.

Why? Practical considerations, in the first place. Reasonable access must be maintained for emergency vehicles. The lanes also should be kept open for buses, which represent a minimal security threat. Allowing buses to pass along the avenue would lighten traffic on nearby streets. And it would do something to enliven the place, to give it a sense of city life. Tour buses -- or, as Brown suggests, an "improved level of public transportation for tourists" -- would be able to make the front of the White House a regular stop.

Then there is the inaugural parade. It's a fine tradition to place the presidential reviewing stand in front of the White House. Should we then alter the parade route and sneak by the back door? Obviously not. The Clinton White House, to its credit, favors the traditional route.

Before there was a White House there was, of course, a bold plan for the capital city. In Pierre L'Enfant's vision, the president's mansion and its grounds were to be unified. In his concept, there was no avenue between 15th and 17th streets NW, and there was no separate Lafayette Square.

But even in the earliest days, says Patrick O'Brien, a historian with the Park Service, there very likely were paths across the presidential grounds. "People were living in Georgetown and traveling to Capitol Hill and back," he notes. "This was a very large piece of property, and they weren't always willing to go around it." By the early 1820s, there was an established right of way, and the White House, the avenue and the park began to take on their separate identities.

This history of both consistency and change could provide a philosophical basis for a new, improved design. James Urban, who created the new plaza surrounding the Hirshhorn Museum, points out that historical layering is the idea behind what might be called a "new humanism" in landscape architecture. Just as responsible architects, when designing a building for a city, take a close look at everything around its site, landscape architects now analyze a site's past for clues to its new structure. Again, it's White House, avenue, park -- separate but indivisible.

Hence, the next slogan -- Remember the White House -- might seem totally unnecessary, except that even very smart people sometimes forget the obvious. The talk of making the new White House plaza into a memorial is stark evidence of this fallibility. The White House is the memorial, the focus, of this site. Its centrality might be subtly enhanced in a new design, but it shouldn't be altered. If it ain't broke, don't fix it.

Remembering the city might seem like a much-abused piety. These days, when someone on the federal side swears friendship for the District, wise Washingtonians hold tightly to their wallets and purses. But we should repeat the slogan like a mantra, because the Pennsylvania Avenue closing has unleashed a sort of separatist movement on the part of the federal government -- every agency wants its own wall, moat and drawbridge. In terms of actual design, this motto stresses integration rather than segregation.

Landscape architect Brown offers a final, optimistic, guideline: "It's an opportunity, not a problem." This is true. A fine new democratic space can be made in front of the president's house. And it won't be necessary to reinvent the wheel to do it.