Donald Trump. AP On Thursday, Hillary Clinton gave a powerful speech about the grave dangers a Donald Trump presidency could pose, such as global economic crisis and nuclear war.

Later on Thursday, Trump made an appallingly bigoted comment, saying that the judge presiding over the Trump University fraud trial — reminder: Donald Trump is a defendant in the fraud trial — could not be impartial because he is of "Mexican heritage" and a member of a Latino lawyers' association.

I do not believe this timing was a coincidence, or an unforced error on Trump's part. I believe it was a deliberate tactic designed to change the subject — one that could work.

Trump would rather have a national conversation about whether he is a bigot than one about whether he is too erratic to be trusted with the nuclear codes. That's because he'd rather argue about whether he's bad for some people than about whether he's bad for everyone.

I don't think either of these topics is great for Trump, and it's fine to say that he's a racist and also that he can't be trusted with nuclear weapons. But I do think that if the campaign becomes a lot about Trump's treatment of non-whites and Hispanics, then Trump is likely to benefit to some degree from a backlash among white voters.

Remember: Half of whites think that racism against whites is as big a problem in America as racism against non-whites, according to a 2015 study from the Public Religion Research Institute. A 2011 study by Tufts psychology professors found that whites rated anti-white racism as a significantly larger problem in America than anti-black racism.

There are an awful lot of white voters who are sick of hearing about bigotry, which they believe to be an overstated problem. Trump was able to win the Republican primary because so many are willing to write off nearly any complaint about bigotry as "political correctness" or special pleading.

The more this campaign becomes about Trump being bad for specific ethnic groups, which he is, the more he will get to send a signal to many white voters — many of whom feel displaced, even if they do not have a valid reason for feeling that way — that he is their man.

On the other hand, the power of the Trump-is-too-risky attack is that it can appeal to all groups that would be harmed by a nuclear war or a global economic crisis — which is to say, people of all races and ethnicities. It's an argument that can build a much broader coalition to defeat Trump.

Trump knows this, and I believe it's why he attacked Judge Gonzalo Curiel for his ethnic heritage.