Who wants to commune with legendary architect Eero Saarinen and design a coda to his transcendent masterwork, the Gateway Arch?

That, in essence, is the invitation that may to go out later this year to the world’s architectural design and planning community. The National Park Service is working to complete a new management plan for the Jefferson National Expansion Memorial, the national park in which the iconic Arch is situated.

In March, the Park Service solicited public comment on a plan that proposed holding “a design competition akin to the 1947 competition” that produced the winning Saarinen design. The competition would “be held to generate ideas to revitalize the Memorial grounds, expand interpretation, education and visitor amenities.”

The Park Service hoped to complete its final plan — including details of the competition — this summer. But now it may not be ready until November.

The 1947 competition took about six months to complete, from solicitation of entries to announcement of the winner. It owed its efficiency and success to solid planning and visionary oversight.

The time is right to get organized for the new competition — to establish and educate a leadership team made up of diverse local and national interests, to line up a world-class panel of judges, and to begin planning the practical work of running a competition from start to finish.

The Park Service deserves credit, not criticism, for taking additional time. The public responded with good ideas for how to make a good proposal better. The Park Service was listening and is considering how some of these ideas might figure into its final plan. For example:

• A consensus is emerging that the competition should not be restricted to just the Arch grounds, but should take in the Mississippi riverfront and connect the Arch grounds to the center city and to the Illinois side of the river.

• The competition should be open to including a new structure or facility on the Arch grounds, carefully situated and designed not to detract from “the essential character-defining elements” of the Arch and surrounding landscape.

• The Park Service has launched a traffic study in response to practical suggestions it received for how to deal with access problems created by Memorial Drive and the depressed lanes of Interstate 70.

All of these elements deserve a place in the final plan for a design competition. If we are calling on the world’s most brilliant architects and designers to propose ways to solve a puzzle, we should make sure they are given all of the pieces.

The Park Service must sort out these details and set the final criteria for the competition. Meanwhile, there’s much work to be done.

Leaders are needed to manage the competition and to raise the approximately $1 million needed to fund it. U.S. Sen. Claire McCaskill, D-Mo., is well suited to help recruit an able team.

Ms. McCaskill already has worked effectively behind the scenes, earning the trust of many parties. She’s helped to move the process forward, both by defending the Park Service’s prerogatives for careful stewardship and by encouraging the agency to be ambitious and responsive.

Ms. McCaskill can help ensure that many points of view are represented among those people overseeing the design competition, that no one dominates the discussion and that the contest can move ahead quickly after the Park Service delivers its final plan.

Jamie Hand, program director at the Van Alen Institute, a non-profit architectural organization devoted to promoting public design processes, had this advice for would-be leaders of design competitions: “Brace yourself to be flexible.”

The best competitions, she says, are run by leaders who are careful listeners with open minds and who work to encourage vision, conviction and solid plans.