State Government purchases are governed by state contracting and bid laws. California can establish criteria for bidding such as to award to a “low evaluated bidder” where some of the criteria include emissions. The could even establish thresholds of emissions that would bar certain manufacturers from bidding, but those thresholds of emissions would need to have a rational explanation and effectively blacklisting a manufacturer for political reasons would not hold up, except in a kangaroo court.
Now then comes the issue of restraint to trade and anti-trust violations. The down side for California is the anti-trust violations often have a cost of triple damages.
Again, this sounds illegal.
I remember how the courts stopped Trump's change to immigration policy because he made some comments about Muslims, even though the policy change was not specific to religion.
This should play out nicely in the new Republican appointed majority 9th Circuit court.
Yes, but if you have the votes, you can do whatever you want. /sarc.