Attorney General Eric Holder said many encouraging things in his important speech on the future of sentencing reform, but the most striking thing may have been what he did not say. In all his 4,000 words on America’s “broken” legal system — and particularly on its outlandishly harsh and ineffective sentencing laws — there was not one mention of executive clemency.

That power, which the Constitution explicitly grants to the president, has always served as an indispensable check on the injustices of the legal system and as a means of demonstrating forgiveness where it is called for. It was once used freely; presidents issued more than 10,000 grants of clemency between 1885 and 1930 alone. But mercy is a four-letter word in an era when politicians have competed to see who can be toughest on crime.

As ProPublica has documented, the pardon process has devolved into a mockery of itself, riven by arbitrariness, racial disparity and charges of abuse. Clemency given to powerful, well-connected individuals like Marc Rich, by Bill Clinton, and Lewis Libby, by George W. Bush, has only increased cynicism about the process.

Meanwhile, President Obama’s use of the pardon power remains historically low. In four and a half years, he has received almost 10,000 applications for clemency and has granted just 39 pardons and one sentence commutation. No one seems to know why some requests are granted and others denied. To call it a lottery is unfair to lotteries; at least if you pick the right numbers, you’re guaranteed to win.