the census is required for apportionment to the house, but today the census is primarily for distribution of funds since it includes those who cannot vote and are not citizens (i.e. underage, temporary visa, illegal). one estimate is that it now costs $3 per person to conduct the census, so over $1Bn, and that number did not factor in the current advertising campaign. The strategy of this census is not apportionment, but distribution of funds, which is why its being managed out of the white house this time around. And of course the opportunity for gerrymandering.