The circus high-wire was never so dangerous as the tightrope being walked now by General Motors and the United Auto Workers. What makes it all the more daring is that the U.A.W., like the Great Flying Wollendas, is balancing the seven-person human pyramid in the form of the Employee Free Choice Act.

According to G.M., it’s survival depends on the U.A.W.’s agreement to change the perpetual, G.M.-financed trust covering health care costs for hundreds of thousands of retired hourly workers and their surviving spouses. Although G.M.’s obligation is estimated to be $47 billion and an example of why it’s on death’s door, the retiree health care provision is a crown jewel of the U.A.W. contract.

But G.M. can’t survive without additional government money. The government won’t give G.M. the money unless it demonstrates long-term viability. After losing $20 billion last year, it’s unlikely that G.M. can convince the government it won’t be throwing good money after bad as long as G.M. must pay an estimated $5 billion a  year in retiree health care benefits.

The Employee Free Choice Act is the legislative crown jewel of organized labor. It would dramatically change labor law and make it much easier for unions to organize groups of employees. It’s a hotly contested proposal. The EFCA battle in the U.S. Senate will be bloody, and it’s far from clear that there are the 60 votes needed to stop a filibuster. Should the U.A.W. become the villain that causes G.M.’s collapse, it jeopardizes EFCA’s passage.

In 1962, the Wollendas’ human pyramid crashed at a performance in DETROIT, killing two members of the family and leaving one paralyzed. In 1998, the sixth generation of Wallendas returned to DETROIT and performed the seven-person pyramid again, this time successfully. Now the U.A.W. will perform the act in DC.