Some Supreme Court justices have become fond of taking guidance from international standards, as in Roper v. Simmons, the recent decision to bar the death penalty for those under age 18. But do not look for the court to condemn cloning, as the United Nations did by a vote of 84 to 34, or to modify abortion policies to bring them into line with the much more restrictive ones of most developed countries. What the justices mean is that we should look to world standards when those standards support their political preferences.
Justice Antonin Scalia, in his Roper dissent, tossed a grenade at the American Psychological Association on grounds of double standards. In an abortion case before the Supreme Court in 1990, the APA said a "rich body of research" showed that by age 14 or 15 people are mature enough to choose abortion because they have "abilities similar to adults in reasoning about moral dilemmas." But the APA's certitude of the strong moral grasp of young teens apparently evaporated just in time for Roper, where they told the court that minors just aren't mature enough to be eligible for the maximum penalty faced by adult killers.
Planned Parenthood adopted a more comic double stance on abortion: Young girls are fully capable of choosing to abort without informing their parents, but they could not enter a Planned Parenthood pro-abortion poster contest without parental approval. The fine print on the contest said, "Children under age 18 must have a parent or legal guardian's permission to submit designs." No, you wouldn't want young teens making drastic poster decisions without input from Mom or Dad.
The Republican threat to invoke "the nuclear option" to break the Democratic filibuster over judicial nominations has brought a mother lode of double standards. For example, law Prof. Erwin Chemerinsky of Duke coauthored a strong antifilibuster law article in 1997 when Republicans were obstructing Democratic court nominees but a strong pro-filibuster argument to meet the current debate.