classification & test:
1)  strict scrutiny:  fundamental rights; race, national origin, aliens (unless gov’t fx exception)
test:  compelling govt interest & narrowly tailored
2)  mid-level review:  gender
test:  imp. gov’t interest + substantially related to interest
Ginsburg:  exceedingly persuasive justification (VMI)
3)  elevated rational basis:  reverse burden
illegal aliens, illegit kids, mental retardation
4)  rational basis