Let's unpack what it says.
"If.. I told you just three would kill you"
The meaning: I have certain knowledge that three of the Skittles in the bowl will kill you.
I'm guessing there are about 100 Skittles in the bowl, though Mr. Trump has used the figure 1,000
So in his scenario, 0.3% of the Skittles are known to be deadly.
To apply the analogy to Syrian refugees, Mr. Trump would need to have certain knowledge that 0.3% of them are known to be deadly terrorists.
Does he have that certain knowledge?
And has our pusillanimous press even thought to ask him that?
But to continue unpacking:
"Would you take" - I assume he means "eat" - "a handful?"
Presumably analogous to the US taking at random some proportion of Syrian refugees.
And if 0.3% of Syrian refugees were deadly, as Mr. Trump appears to claim, that would indeed be a concern.
But we do not take Syrian refugees at random. There is a long drawn out screening process.
So to continue Mr. Trump's analogy, we should add:
"And if I told you we had screened out the Skittles that would kill you, would you take a handful?"
If I enjoyed eating Skittles, well yes, I would.
And if common humanity impelled me to give refuge to
" your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore."
...well, yes, I would.
Chris Hayes and Ken Burns discuss the subject.