Former U.S. Sen. John Danforth has exhorted the St. Louis region to “think big” about the future of two of its transcendent assets — the Gateway Arch and the Mississippi riverfront.

He sees both as moribund, for all of their majesty — as a poorly connected, needlessly passive, inaccessible world apart from the lives of the community and everyday people they should be serving.

Last weekend about 35 student architects, engineers, artists, and landscape architects from Midwestern universities descended on downtown St. Louis. Their 30-hour mission: Explore “fresh, new possibilities” for reconnecting and revitalizing the riverfront, Arch grounds and near-downtown district.

The students came at the invitation of the St. Louis Chapter of the American Institute of Architects and members of St. Louis’ professional design community. They convened at downtown’s Mansion House and worked as teams, the panorama of the Gateway Arch and Arch grounds before them.

The first lesson the students learned was about the tension that Mr. Danforth’s proposal has created.

At a panel discussion Friday evening, Danforth Foundation President Peter Sortino argued the Arch grounds need to be re-energized, possibly by a brilliantly designed iconic structure that respects the Arch’s “magnificence.” This structure also could help revitalize the downtown riverfront, Mr. Sortino said.

But Tom Bradley, the National Park Service’s superintendent for the Arch, reminded them that the American people had set aside the Arch and parts of the Arch grounds to be preserved. He urged the student teams to look beyond the park boundaries when considering strategies.

There was plenty of tension in the students’ own deliberations:

• The Arch is a protected part of the nation’s history. But a significant piece of the nation’s history — a large 19th-century cast iron warehouse district whose architectural significance rivals New York City’s SoHo — was razed so it could be built.

• Communities rightly get excited by the possibility of a new architectural treasure — what one student referred to as “another wow.” But shouldn’t such a structure be just one element of a much broader strategy to reverse downtown inertia?

The student teams worked to reconcile these and other paradoxes while mapping their visions for what might be.

All of them wanted to tear out the tangled barrier of drives and depressed lanes that isolate downtown, the Arch, and the Riverfront from one another.

Otherwise, imaginations diverged.

Some held that nothing is sacred about the Arch grounds, which they saw as due for radical reordering. Others saw the park’s captivating remove as irreplaceable and critical to the city’s long-term future and focused their planning on how to connect people to the park and rebuild the nearby community.

At the end of the process, the students presented their ideas with precision, passion and provocation — totally unencumbered by the layers of politics and manners that so often inhibit local civic conversations.

(The public can view the proposals at an exhibit soon to be set up at the Landmarks Association of St. Louis’ gallery at 911 Washington Avenue.)

It’s doubtful such a discussion would have been held were it not for Mr. Danforth’s challenge. Or that the National Park Service would be considering putting another generation of brilliant minds to work on a new design competition.

The last one, in 1947, yielded the Eero Saarinen masterpiece that symbolizes this city.