Under federal law, it is no longer per se illegal for a manufacturer to agree on resale prices with its distributor. State laws still vary, however, and even under federal law the practice can be unlawful under a detailed market analysis that weighs all the pro-competitive and anti-competitive effects of the resale price maintenance.
However, manufacturers and distributors can avoid these complexities if they do not agree on resale prices, but agree on minimum advertised prices. The distributors are free to set their own prices, but if they want advertising co-op funds (or other benefits), then they cannot advertise lower prices.
I’ll post more on MAP programs in a bit.