A key argument used by Senate Democrats defending the National Labor Relations Board during a hearing this morning was that while an appeals court had ruled in January that two of President Obama’s recess appointees to the board were unconstitutional, other courts had not. Therefore, the NLRB was right to ignore the ruling at least until the Supreme Court could decide the matter.

Well, that changed Thursday, Politico reports:

A second appeals court has joined the D.C. Circuit in ruling that President Barack Obama’s recess appointments to the National Labor Relations Board were unconstitutional, concluding that some board actions taken in the wake of those appointments were also invalid.

The issue has far-reaching implications for both the NLRB and other boards, including Obama’s Consumer Financial Protection Bureau, which has been a frequent target of conservatives and whose director was a recess appointment.

The 2-1 decision Thursday from the U.S. Court of Appeals for the Third Circuit (posted here) found that the presidential recess appointment power is limited to breaks between sessions of Congress, not breaks within sessions or other adjournments during which the Senate might meet in pro forma sessions. The reasoning mirrors that in a ruling of the D.C. Circuit Court in January.

The 3rd Circuit case centered on decisions the NLRB made on the authority of three members including Craig Becker, who was appointed by the president on March 27, 2010, while the Senate was adjourned for two weeks.

Becker has since left the NLRB, but the ruling adds weight to claims by the board’s critics that it and the administration has acted unconstitutionally ever since the Obama administration took office.

The NLRB has not issued a statement so far.

Mark Mix, president of the pro-business National Right to Work Legal Foundation, said in a statement emailed to reporters:

Today, another federal appeals court has invalidated one of President Barack Obama’s so-called ‘recess appointments’ to the National Labor Relations Board. As National Right to Work Foundation attorneys have argued in several courts, the Obama ‘recess appointments’ have clearly violated the U.S. Constitution.