I'm just going to sign it and turn it back in.
The problem with that is that it can be good or bad depending on where you live. If you live in a region/state with a lot of illegals that will fill out the form without the citizenship question, then by not participating in the census, you are "cancelling out" their vote so to speak. If you live in a region/state that has few illegal aliens, you want to fill it out so that you contribute to potentially adding more representation in Congress, or protecting your current representation.
I believe there are several states that are on the cusp of getting an extra congresscritter taken from another state. IIRC, the new congresscritter will likely end up dem in most of them, partially bolstered by non-citizen participation in the census if there is no citizenship question.
I believe the largest potential seat gains will be in Florida and Texas. Lots of conservatives move to those states, but then so do many liberals, and they both have likely high illegal populations.