What Law—Specifically—Would Have Prevented Yesterday’s UCLA Shooting?

From Charles C. W. Cooke at the National Review:

As soon as the story hit the news, the usual suspects began cranking themselves up. Americans, they said, need to “do something.” It was time, they argued, for “more laws.” And the NRA? It was, of course, to blame.

Forgive me for being a broken record, but I have some questions in response to these reactions: Namely, “what something?”; “which laws?”; and “what, specifically, did the NRA do wrong here?” Rolled into one, these congeal into a single, simple inquiry: “What law — specifically — would have prevented yesterday’s shooting?”

I ask because, absent the total ban on firearms that gun-control advocates insist that they don’t covet, it is not at all obvious which rules would have stopped the perpetrator from carrying out his plan. According to the Los Angeles Police Department, the shooter bought a 9mm handgun legally in Minnesota, passing a background check in the process; then, gun in hand, he killed a woman in that state; and, finally, he drove with his guns to California, where he killed both his professor and himself.
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During his presidency, President Obama has proposed three substantial changes to the legal status quo: 1) the imposition of mandatory instant background checks on each sale or transfer of a firearm, including those sales and transfers that are conducted entirely privately; b) a hard limit on the capacity of commercially available magazines; and c) a ban on so-called assault weapons. But none of these proposals even intersects with this case. The shooter passed an instant background check in Minnesota; his murders did not involve or require him to “spray” bullets or even to reload; and he did not use an “assault weapon,” but a common handgun.

Well?