The Democrats’ two-track plan for getting U.S. President Joe Biden’s legislative agenda through Congress is threatening to become a four-way train wreck among moderates and progressives in the House and Senate.

While they debate the who, the how and the when, the real trouble is the why.

Making laws is always messy, and the details, timing and logistics of these particular bills may be especially so. But it would be a mistake to say this is the main problem. The sticking points are not the allegedly unreasonable stance of Arizona Sen. Kyrsten Sinema or which chamber should go first. The problem is a lack of vision: What is the guiding principle of this legislation?