The Court

The evolving standards of decency "test" applies only to the eighth amendment, but you're not incorrect to relate other cases such as the issue of gay marriage. Although the evolving standards test is not used in other cases, the same mindset is at work. It basically boils down to we like it (or we don't like the thought of outlawing it) so the constitution must protect it. It's the notion that the constitution protects everything we (5 judges) think is good. Tomorrow it means something different than it did yesterday until our constitution doesn't constitute anything.