Oh, come on, John. Cruz didn't shut it down by himself, it had minimal effect on the day to day lives of.. anyone, and R approval ratings actually went up after it.
The point is... this is one of the lines of attack that will be used. (I'd also point out it had a significent effect of our troops and their families. And that was communicated to their extended families.)
The response will be weak to the eyes of the undecided.
And we've been consciously choosing candidates for the last 8-12 years that are very easy to attack in the general, despite running better choices in the primary.
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I'm not too happy with Cruz; but if he's the only way to stop Trump, I can deal with it. I've long argued a Rubio/Kasich ticket to be the best chance we had for a general election victory, though.
Unfortunately, too many conflate GOP primary voter patterns as how the general plays out. And then are shocked when that doesn't happen. (The "it's gotta be voter fraud" meme is, in my view, denial.)