"Perhaps the greatest caveat to the backdoor Roth contribution strategy, though, is the so-called 'step transaction doctrine', which allows the Tax Court to recognize that even if the individual contribution-and-conversion steps are legal, doing them all together in an integrated transaction is still an impermissible Roth contribution for high-income individuals to which the 6% excess contribution penalty tax may apply. Fortunately, though, the step transaction doctrine can be navigated, by allowing time to pass between the contribution and subsequent conversion ... But perhaps the easiest way to avoid the step transaction doctrine is also the simplest ... stop calling it a backdoor Roth contribution in the first place!"