After laying a decades-long siege to the labour fortress of Sunday penalty rates, employers have finally loosened a few bricks, allowing some to clamber over the wall.

The Fair Work Commission has partially validated their claims that exorbitant Sunday rates had been a handbrake on investment, jobs, growth, and on choice for consumers.

The decision is a victory for capital's revised tactical demand for incremental reductions.

Even so, the micro-economic benefits remain contested, the individual effect of the cuts harsh, and the politics therefore, dangerous. How much? For Malcolm Turnbull, think WorkChoices-dangerous.