What did Donald Trump do today?

He claimed, via his press secretary, that it was "impossible" to know how many people with pre-existing conditions would be priced out insurance under his ACA replacement bill.

Coverage for people with pre-existing conditions, a key feature of the ACA (also known as Obamacare) is popular with Americans across the political spectrum. Trump's version of a replacement allows states to waive that requirement, at which point people who could not afford private insurance would have to purchase it from state-run "high-risk pools." An independent analysis by AARP concludes that premiums for people in this group could reach $25,700 in its first year.

Some people are born with conditions that made them permanently uninsurable before the ACA was passed. About 40% of Americans have a "declinable" injury or illness by the time they reach Medicare eligibility age. Under Trump's plan, any such person who lost their insurance for any reason would be forced into the risk pools. 

Sean Spicer, asked about the apparent disconnect between the funding for the risk pools and the expected number of people forced into them, claimed it was "literally impossible" to calculate such things. It is not. 

Why is this a bad thing?

• As a rule, good policy isn't built around critically important but totally unknowable facts.

• There's a difference between not knowing something and not being willing to admit something.