It's very... sanguine of you to think the Supreme Court is full of bloodless rationalists, computers that read statutes and, via sheer force of deductive reasoning, come to a conclusion.
In reality, the Supreme Court is supremely political, and they regularly do shoot down a law because they think it sucks or approve a law because shooting it down would make people angry.
The situation is quite a bit more nuanced than that. The court will certainly go to substantial lengths to find a way to uphold a popular law or strike down a bad law, but they don't make things up out of thin air.
It's not striking down a law, but you can see the process at work most clearly in Bush v. Gore. It was, on the face of it, a horrible decision, and the court itself said it shouldn't be used for any precedent; it's not been cited once since then.
But it isn't merely a matter of disagreeing with the decision. It's the crass politicization of it. If you look at the breakdown of the vote, the Justices who supported Bush supported Bush, and those who supported Gore supported Gore. (Thomas's wife was heavily involved in Bush's campaign, and O'Conner had said the evening before the election that she'd find Gore's election personally disastrous.)
Nor can ideology account for the decision: the same justices who are pretty stingy when it comes to applying Fourteenth Amendment rights generally suddenly found it imperative to extend it to a radically new situation in an usurpation of state rights with federal judicial might. The converse was also true, as the Justices usually distrustful of states running their own elections suddenly thought that sacrosanct.
Edited to add a particularly damning quote:
"The counting of votes that are of questionable legality does in my view threaten irreparable harm to petitioner Bush, and to the country, by casting a cloud upon what he claims to be the legitimacy of his election. Count first, and rule upon legality afterwards, is not a recipe for producing election results that have the public acceptance democratic stability requires." IOW, Scalia is banning the recounting of the votes of undecided legality because it might make Bush's election look less legitimate and cause political turmoil.
> It's not striking down a law, but you can see the process at work most clearly in Bush v. Gore. It was, on the face of it, a horrible decision, and the court itself said it shouldn't be used for any precedent; it's not been cited once since then
Bush v. Gore is like a once in history Constitutional crisis. It's not representative.
In reality, the Supreme Court is supremely political, and they regularly do shoot down a law because they think it sucks or approve a law because shooting it down would make people angry.