It can't pass legislation, but it can issue an executive order. http://en.wikipedia.org/wiki/Executive_order

However, an exec order for cell phone unlocking would be a tremendous waste of political capital.

An executive order would also probably be a waste of time because it is irrelevant; the FCC is an independent agency and not directly overseen by the Executive Branch. The President appoints commissioners but Congress has to approve them and they do not report to him/her.

And more importantly, an executive order can be ignored by any subsequent presidency. This change needs to be in law for it to have any teeth.

Unfortunately, that kind of stuff takes time.

And probably illegal, since the LoC was explicitly given this power by Congress.

Refuse to enforce this clause of the DMCA and pardon anyone imprisoned because of it.

Has this actually been enforced against anyone so far?

Whether it actually gets enforced doesn't matter, what matters whether people refrain from engaging in the activity (or aiding others in doing so) because of the risk that it could be.

There's always that risk with unenforced laws - there's hardly ever (ever?) a stated policy of non-enforcement, since the executive is also technically obliged to enforce everything congress has told it to.

I would generally be interested to know if it ever has actually been enforced so far.

Those are civil suits - not criminal enforcement that the administration could choose to pursue or not

Sklyarov was arrested.

Is that the part of the DMCA we're talking about here?