This is what happens when you ban the US census

You lose the power to pass legislation you want.

For the groups who thought that boycotting the US census was the best course of action in terms of protesting the lack of attention you get as a demographic, you got what you deserve, less political power as a state.

If you really want comprehensive immigration reform, you have to show that you exist!  You have to be counted and stand out a through a nationwide census!  To hide from the census just means you'll never get the reform you seek, so why boycott it?!  Oh well, I guess the comprehensive reform you seek will have to wait another ten years, when you wise up to the consequences of boycotting the census.

I doubt that New York or New Jersey were affected by any boycott of the census but to lose seats in both of these states can be a bit scary.  But I suppose the Latino representation in congress will be stronger in future elections in the southern-border states.