In August 1968, at the third IAEA fusion conference in Novosibirsk, Lev Artsimovich announced that the Soviet T-3 tokamak had reached electron temperatures of 1 keV — ten times better than anything the West had. The claim was so implausible that the British sent a team from Culham with a ruby laser Thomson-scattering rig to measure it themselves. In 1969, they confirmed it. The reaction inside the American fusion program was catastrophic.

Princeton's Plasma Physics Laboratory had spent the entire 1950s and 1960s building stellarators — a fusion device invented by Lyman Spitzer in 1951, using twisted external magnet coils to confine plasma in a figure-eight or helical torus. No plasma current was needed; the magnetic geometry did all the work. The flagship Model C stellarator, operating since 1961, was the most sophisticated plasma physics machine in the world. But its temperatures were stuck at 400 eV. Spitzer's team blamed "Bohm diffusion" — anomalous transport that seemed fundamental.

When the Soviet tokamak numbers hit, Melvin Gottlieb made a decision that shaped fusion for 50 years: he ordered Model C converted into a tokamak. In four months during 1969, the stellarator's beautiful helical coils were ripped out and replaced with a simple axisymmetric configuration. The rebuilt machine — the Symmetric Tokamak (ST) — hit 1 keV within months. Every stellarator program in the U.S. was killed. Oak Ridge, Livermore, MIT — all pivoted to tokamaks. The Wendelstein program in Garching, Germany, was the only significant Western stellarator effort that survived, and only because Germany refused to follow Princeton.

Here's what nobody realized until the 1990s: tokamaks require a huge toroidal plasma current, which means they can only run in pulses, they suffer catastrophic disruptions when the current collapses, and they need enormous external heating and current drive to sustain. Stellarators have none of these problems. They're inherently steady-state. They don't disrupt. Spitzer was right; the physics community just didn't have the computational tools to design a good one.

Wendelstein 7-A ran from 1975 to 1985 with only classical coils and did solid work. Its successor W7-AS (1988) added modular twisted coils optimized by early supercomputers. Then Wendelstein 7-X, completed in Greifswald in 2015 after 19 years of construction, used 50 superconducting non-planar coils shaped by full 3D MHD optimization codes that didn't exist in 1969. In 2023 it sustained an 8-minute plasma pulse at 30 million degrees — the longest steady-state high-performance fusion plasma ever produced. In February 2025 it hit a triple-product record above 10²¹ keV·s·m⁻³.

Why the second look now? Three things changed:

• Optimization codes: VMEC, STELLOPT, and modern GPU-accelerated MHD solvers can design coil geometries impossible to hand-calculate in 1969.
• High-temperature superconductors: REBCO tape lets you build twisted coils with fields that Spitzer could only dream of, at plausible cost.
• Additive manufacturing: the non-planar coil forms that killed the 1960s program are now printable.

Type One Energy (Wisconsin) and Proxima Fusion (Munich, W7-X spinoff) are both building HTS stellarator power plants targeting the 2030s. The tokamak world just spent $25 billion on ITER to prove burning plasma physics; the stellarator world is quietly walking into steady-state operation while ITER argues about disruption mitigation.

Model C was bulldozed in a panic. The panic was wrong.