What legal principle or court ruling precludes laws targeted at a specific individual or group?

the voter-ID law is being challenged because (allegedly) the practical effect is to discriminate against constitutionally protected group - by race. A lot more poor people are minorities, a law that hurts poor people disproportionately a lot more, hurts minorities a lot more. The alleged problem being addressed (people voting fraudulently) is nowhere near the level alleged by proponents of the legislation, so the law puts excessive demands on poor=minoritis for no good reason. It can be argued that it was in fact designed to do this - stop minorities who more often vote Democrat from doing voting at all unless they go to extreme lengths. the obstacles to obtaining proper ID are much greater for poor people; they likely don’t have computers, they likely don’t have the free time or automobile to travel a long distance to apply for things like birth certificates in person, they are less likely to have this sort of documentaton already, yada yada.

You see the case - voter ID = stop protected minorities from voting is the argument. Therefore, the law unfairly targets a constitutionally PROTECTED minority. If true, this is unconstitutional. Bill of Attainder etc. have nothing to do with it.

Writing a bill to target densely populated area - class 1 , 2 etc. - faces no such challenge, unless the result is to effectively discriminate against a protected minority. Challenges over discrimination have had two attacks - the intent was to discriminate, or the net effect is to discriminate. (I.e. unecessarily demanding physical standards had the net effect of discrimanting against female firefighter or police applicants, whether intentional or not.) While generally unintentional results don’t qualify as discrimination, if they are too obvious then they may.

The trouble with passing a too targetted law is this - what would stop Walmart, for example, from contracting with a separate Wal-Consultant-Mart, inc. to provide the people to work its stores, who were not then employed by Walmart? However, a law that covered “everyone over X employees except the following” prevents a silly end run. Of course, i’m surprised WalMart didn’t just franchise out half its stores to bypass this rule.

Md, to clarify, as in your example, that is PERCEIVED targeting, the SPECIFIC wording of the law does not say that it is directed at minorities, but it’s application could be so.

To clarify, if, the text of the law is unclear or vague, then the courts decide, my other post was directed at the posters intent, when a SPECIFIC group is targeted, his words:

As cited above there are many other kinds of possible bills “targeted at specific individual or small group” other than a bill of attainder that are entirely legal. That’s the distinction that everybody has carefully been making.

Not even dicta:

VILLAGE OF WILLOWBROOK, et al. v. GRACE OLECH.

But as you say, that just means an equal protection claim can be brought based on a class of one; it doesn’t mean that a law can’t ever be passed that targets a class of one.

Also, I don’t know what the other thread that’s being referred to is, but this part of the OP:

[QUOTE=dstarfire]
In a recent thread one flaw with a posted theory/idea was that it involved a law targeted at specific individual or small group (and not a member of an explicitly protected group like race or religion).
[/QUOTE]

sounds backward. It’s harder to legally justify legislation that targets individuals in an explicitly protected group. Again, that’s not to say you can’t do it; there’s no blanket ban on passing laws that affect this group or that group or this person or that person, but depending on the law and the group it might be either really easy to get away with or nearly impossible.