After 41 years of court challenges to Roe vs. Wade, American abortion law is becoming a dense thicket of case law that makes tea-leaf reading difficult when jurists decline to explain their decisions.

That is what happened earlier this month when the U.S. Supreme Court decided not to hear a case involving an Arizona law limiting when a woman could seek an abortion.

Last May, the 9th U.S. Circuit Court of Appeals overturned a federal judge’s ruling that Arizona’s 2012 law House Bill 2036 was constitutional.

In its decision, the appeals court panel noted that “controlling Supreme Court precedent” forbids states from denying women the right to an abortion “at any point prior to viability.”

Viability — the ability to survive outside the womb — is generally considered to occur at 22 to 24 weeks, not at 20 weeks.

The appeals-court decision affects only Arizona, however.

At least nine other states have laws that ban abortions at 20 weeks, and those laws will remain in effect. If that seems confusing, it should.

It may be that Arizona’s law pushed the viability envelope a bit too far. The law is structured so that, in practice, it could affect pregnancies that are only 18 weeks along.

Regardless, we know what the outcome of this non-decision by the high court will be: The process will begin anew.

Advocates who oppose abortion already have declared their intent to bring a new proposal to the Legislature, where it’s likely to pass.

Then, it is off to the courts once again. Lawyers need not fear unemployment.

— Arizona Republic, Jan. 13