The constitutional pardon power is best known for its association with historic events like Watergate, which is why it is generally discussed in terms of the worthiness of its beneficiaries, rather than the god-like authority it vests in the president alone. There are only theoretical restrictions on the scope of federal lawbreaking the president has the power to forgive. But precisely because the power is so broadly applicable, and so narrowly held, its potential for abuse is tightly circumscribed by politics. Presidents might be tempted to pardon many people, but few want to answer for why this or that high-profile felon or suspect deserves leniency when others don’t.

There is a regular exception to this dynamic, though. The end of every presidency eases political constraints considerably, and makes the pardon power a potential source of incredible good or, as in Bill Clinton’s pardon of Marc Rich, gross impropriety.

President Barack Obama has been relatively stingy with the pardon power over the past eight years, but he has an important opportunity in this final week of his presidency to use the power in a way that pays lasting political dividends, and signals his belief that the Trump era will be a trying one for liberal democracy.

Even Edward Snowden’s most strident critics must now accept that his surveillance state disclosures, though illegal, were historically significant. The revelation that the National Security Agency engaged in the bulk collection of metadata logging the communications of nearly all Americans was particularly explosive in the U.S.; the all-seeing power of XKeyscore, which, per Snowden’s leaks, gives spies access to Internet user data all over the world, had a chilling effect on dissidents, journalists, and others both here and abroad. Taken together Snowden revealed an incongruity between what the public wants done in its name (or to the public itself) and what the government is doing, making him the totem for an international privacy movement.

As the extent of the impact he had on the debate over government and corporate data collection became clear, his critics and sympathizers sorted themselves into three main camps.