http://www.ageofconsent.com/alabama.htm

In Alabama, the age of consent is 16, yet the age for marriage is 14. This
would mean that in theory, married children ages 14-15 cannot legally have sex,
although failure to consummate a marriage is usually grounds for annulment.
Right there we have an equal-protection issue that would have to be resolved by
making the marriage age 16 or the age of consent 14. If the latter occurs,
then Sherzer's team could next attack the law under which he is being tried.

If the age of consent in Alabama is recognized as 14 (since a conviction for
having sex with a 14-15 year-old would be unconstitutional as married children
that age can legally have sex), then having sex with a 15 year-old would not be
illegal. In that scenario, Sherzer wouldn't even be breaking the law because
15 would be legal in Alabama.

The next step would be to attack the constitutionality of the federal law,
which effectively creates a national age of consent of 18. The states can
argue that this is a states-rights violation and that the feds have no business
telling the states what their age of consent laws should be. Sherzer, as an
adult, is free to travel anywhere he wants, and the law of the land of the
girl's home state should be the issue, because she never left. Sherzer is
theoretically free to relocate anywhere he wants and his first amendment right
to freedom of association would otherwise be impinged.

At most, the federal law should be predicated on the age of consent for each
state. It should not be illegal for a man to travel to a state where a female
is over the age of consent in that state, because it's not illegal to travel,
and it's not illegal for her to have sex with residents of her own state (equal
protection again).

The state of Alabama has more or less said that 14 year-old females can have
sex and it is not a crime (if they are married). Is it the state's business to
criminalize the exact same conduct because someone is not married? If so,
Sherzer's crime would be not marrying the girl prior to having sex, which would
then make premarital sex a crime.

Constitutionally speaking, the government's case looks like a house of cards
waiting to be dropped.

If the latter occurs,
then Sherzer's team could next attack the law under which he is being tried.

Sherzer doesn't have a legal "team". He has a federal public defender who is
unlikely to mount much of an appeal after a (likely) conviction.

Constitutionally speaking, the government's case looks like a house of cards
waiting to be dropped.

Maybe with a rich celeberity but it's not going to be this case.