In short, because it would make the latter confront the fact that he has pursued illiberal, power-hungry authoritarian Bush-esque positions when it comes to foreign policy, and no other Republican candidate would challenge him about it. Glenn Greenwald gives the, provocative, powerful, longer story, with devastating hyperlinks. This was from a while back now, but it’s too important not to get up on here:
He has slaughtered civilians — Muslim children by the dozens — not once or twice, but continuously in numerous nations with drones, cluster bombs and other forms of attack. He has sought to overturn a global ban on cluster bombs. He has institutionalized the power of Presidents — in secret and with no checks — to target American citizens for assassination-by-CIA, far from any battlefield. He has waged an unprecedented war against whistleblowers, the protection of which was once a liberal shibboleth. He rendered permanently irrelevant the War Powers Resolution, a crown jewel in the list of post-Vietnam liberal accomplishments, and thus enshrined the power of Presidents to wage war even in the face of a Congressional vote against it. His obsession with secrecy is so extreme that it has become darkly laughable in its manifestations, and he even worked to amend the Freedom of Information Act (another crown jewel of liberal legislative successes) when compliance became inconvenient.
I’ll leave it there, but it goes on. If you only make time for one long article this week, make sure it’s this one.