Objects may be the lifeblood of museums, but sometimes open spaces, such as the hallway delineated by majestic white columns at the National Museum of American History, also compel our attention. Like other Smithsonian historic spaces, this re-creation of the Cross Hall of the White House closely resembles the real article, down to the same Roman Doric capitals, cornices and pilasters that greeted Presidents from Theodore Roosevelt to Harry Truman. Rooted in antiquity, such architectural elements were popular in America in the 18th century. But their serene authority here bears the lasting mark of the 20th century — and of a few of its strongest wills.

Today, we take for granted that the President lives and works in the White House, with its elegant parlors of various hues and shapes. But back in 1792, when James Hoban presented his design for an executive residence to President George Washington, no one knew exactly what the President’s Palace, as it had been fancifully termed, would — or should — be.

An immigrant from Ireland, Hoban drew inspiration for his design from an aristocratic Dublin house. For the Presidential dwelling, he inked a plain first-floor entrance hall set off by columns from what would become an 80-foot-long transverse hall connecting all the first floor reception rooms. Though it seemed immense, Washington was unperturbed. The President’s house, he wrote Thomas Jefferson, “ought to be upon a scale far superior to any thing in this Country.”

And for more than half a century, it was. With room for the country’s business and the President’s domestic life, the Executive Mansion was probably America’s largest house until the Civil War. When not holding large dinner parties in the capacious entrance hall, President Jefferson arranged for antlers, pelts and Indian costumes brought back by explorer Meriwether Lewis to be displayed there.

But as the growing country demanded more of its Presidents, so it did of the building that housed them. By 1900, the Executive Mansion was clearly overburdened, and not just by office seekers wanting audience with the President, whose second-floor offices were crammed next to the family’s living quarters. When more than 40 guests came for dinner, the Cross Hall was pressed into service for the inevitable overflow from the small state dining room at the west end. The addition of pipes and wiring had carved up old supporting structures. From the 1880s on, large receptions were preceded by a shoring up of the shaky floors with 10-inch by 10-inch timbers.

Some attempts at fixes created quite unforeseen problems. When a pair of fireplaces on either side of the entrance hall failed to prevent the adjacent Cross Hall from becoming a wintry wind tunnel, a glass screen was placed between Hoban’s slender Ionic columns. Problem solved — at least until the screen’s redesign in 1882 by Louis Comfort Tiffany. With red, white and blue glass set with Tiffany’s signature flair, the screen turned the once plainly Federal Cross Hall into a strikingly mismatched, if memorably colorful, mosaic.

Not surprisingly, by the turn of the century, tearing down or significantly altering the tired manse had been bandied about for years. But the nascent 20th century brought new ideas, including renewal of the city of Washington itself. Deploring the undifferentiated mass of trees, railroad tracks and scattered buildings where the National Mall now stands, the newly formed McMillan Commission called for a sweeping vista from the Capitol to the Potomac, lined by neoclassical buildings. Like President Theodore Roosevelt himself, Senator James McMillan, the commission’s godfather, wanted to preserve the Federal splendor of the President’s home in the redesigned city.

Ironically, the White House, as it had been officially named by Roosevelt, was a far cry from the commission’s vision. Heavy Victorian decoration overwhelmed the once simple interior, including oversize chandeliers, abundant furniture and, not least, Tiffany’s fantastic screen. By 1901, the East Room (at the east end of the Cross Hall) was so crowded with potted palms and settees that it resembled a jungle from which the rambunctious Roosevelt children sprang like wild animals. To make space for her large brood, First Lady Edith Roosevelt sought help from architect Charles Follen McKim of the eminent firm McKim, Mead & White. Renowned for his design of the Boston Public Library, McKim also served on the McMillan Commission. If anyone understood classical design and the clean lines of grandeur, it was McKim.

His solution for the Roosevelts was more than the mere redecoration commissioned by prior Presidents. In his inspection, McKim found electric wiring “not only old, defective, and obsolete, but actually dangerous” and noted that the second floor had settled so much that a new floor was needed. Such “perils to health, and even to life itself,” McKim loftily concluded, meant only radical change.

Ordered by Roosevelt to complete the work in just six months, McKim in 1902 reshaped the White House to close to what we see today. The President’s offices were moved into a new wing to the west. Instead of crowding the entrance hall, visitors now entered through a rebuilt east wing. The state dining room was enlarged by relocating the grand staircase to the other end of the Cross Hall. Down the hall, an oak-paneled elevator provided transport for the President — and, on one memorable occasion, for Algonquin, the Roosevelt children’s pet pony.

But McKim’s biggest changes went beyond structure. Never in thrall to elements of the past he did not revere, McKim grandly swept away the 19th century. Out went the masses of plants and heavy furniture — and the Cross Hall’s Tiffany screen. In their place came classically inspired furnishings underscored by architectural detailing that recalled ancient Rome and Greece with more than a touch of Beaux Arts fantasy.

Brilliantly white Roman Doric columns, entablature and ceiling moldings now graced the Cross Hall, with electrified bronze torchères standing by doorways like sentinels. The effect, critics noted, was chilly, if noble. Even though McKim called this a restoration, the White House’s real past was scarcely grand enough: among other early trappings, Hoban’s own Cross Hall columns were relegated to trash.

Forty-five years later, the full cost of such speedy work was realized. President Harry Truman watched in horror as a chandelier swayed forebodingly in response to a military color guard’s march across a crowded reception room. Investigators determined that the White House was again dangerously unstable. Besides age, the main culprit was haste, from McKim on, in making needed repairs.

Under Truman’s orders, the White House was carefully demolished, until the only thing that remained of Hoban’s original were the outside walls. Then, over a steel frame, the White House rose anew, with many of McKim’s decorative motifs painstakingly re-created. Even though the demolition and rebuilding took nearly three years, no one was more convinced of the need for such drastic action than Truman himself. “It’s a shame the old White House had to fall down,” he wrote. “But it’s a godsend it didn’t when we had 1,500 people in it.”

Today, tours of the White House pass through the Cross Hall upon exiting. Visitors to the Smithsonian’s re-creation of it, however, step into it as callers to the White House used to do, from the entrance hall. Directly in front, and standing on either side of a doorway with a 1902 Presidential seal above, are two of Charles McKim’s bronze torchères (the others are still in their place in the real Cross Hall). At one end of the hall stands McKim’s elevator (complete with Algonquin model) and a trompe l’oeil depicting McKim’s enlarged state dining room. At the other is a trompe l’oeil of McKim’s grand staircase and a richly curtained doorway to the would-be East Room.

Like the original, where the President escorts guests to state dinners, this hall is both ceremonial and functional. Here, First Ladies Barbara Bush and Hillary Clinton have presented their inauguration gowns to the Smithsonian, for the adjacent First Ladies exhibition.

The scale of this re-creation may be smaller than that of its model, but this work is no less original. Terry Conable, the Smithsonian’s chief of historic restoration, used McKim’s masters for the moldings, along with molds and profiles he himself took of the Cross Hall’s door frames and egg-and-dart ceiling molding. He also took an impression of the 1902 Presidential seal and placed it above the hall’s center doors.

That seal, it turns out, holds special meaning for Robert Giannetti, a master plasterer who collaborated with Conable on this project. According to family legend, Giannetti’s father, George, had been working on the Presidential seal in another part of the White House when President Franklin Roosevelt came by to survey his work. Why, asked George Giannetti of the chief executive, did the eagle on the seal face the arrows in its left talons and not the olive branches in its right? Wouldn’t facing the symbol of peace be better than facing the symbol of war?

In October 1945, President Truman ordered the change in the seal. It still graces the Cross Hall today.

By Valerie Jablow