900nm laser emissions ARE legal and effective in all US states currently. The MT-Blinder and others are not effective within about 300 feet or so. The unit just extends your laser-warning time by several seconds so you can react and slow down in-time (hopefully). It does not make you immune to laser law-enforcement (LEO) guns.
Bel RX-series and Passport/Escort also have adapters with their radar detectors so "laser shifting" (ahem) is initiated once detected by the radar detector. Tests show that the Blinder, Escort, and Bel versions are about 90% reliable.
Ka, K, X-band emissions below a certain wattage is also legal (I believe it's 2.5 watts) but Kustom K, etc., police radar guns are on the range of 11 watts so it's pointless.
Passive jamming is snake oil.
Active jamming isn't enough for it to work within the legal sense and most on the market are analog which is pointlessly too slow to react to digital guns, and digital jammers are far far far too pricey (ie. $5000 or so + illegal wattage) and a bit bulky.
I believe radar detectors are illegal in Washington DC, Virginia, and Connecticut only. Laser jammers are not illegal in any state.