It’s always a little tricky to determine exactly how lower courts will apply a rule of law that develops from a U.S. Supreme Court.

Take the case of University of Texas Southwestern Medical Center v. Nassar, decided in June, which held that a “but for” standard (i.e., that an employer would not have taken an adverse employment action but for an improper motive), ought to be used in deciding Title VII retaliation cases.

Would the case apply retroactively (in other words, to all Title VII cases pending in the federal courts at the time)? And would the case make a difference in how cases were decided?

A recent decision by the District Court of Connecticut answers both questions with an unequivocal “yes”.

The decision, Cassotto v. Potter, ostensibly addresses post-trial motions brought by an employer after a trial.  While those motions were pending , the Supreme Court issued its decision in Nassar.

Notably, the district court states what many of us had long presumed — that the Nassar case applies retroactively.  “Where the United States Supreme Court applies a rule of federal law to the parties before it, that rule is to be given full retroactive effect in all cases still open on direct review and as to all events, regardless of when they occurred,” says the court.

Having found that the “but for” standard should apply, the Court was then tasked with determining what should happen to a case that had already been decided by a jury using a different standard.

Because the jury in Cassotto, used a different standard to evaluate the evidence (namely that retliation was a “substantial or motivating factor”), the District Court says the employer is entitled to a new trial using this heightened causation standard.

For employers, the case is further support that there is a new sheriff in town on Title VII retaliation cases; the “but for” causation standard is here to stay and it ought to be raised at each step to ensure that the employer’s decisions are given appropriate support.