When the fascists screamed bloody murder over migrants, the liberal response was not to fight them on it, but to show their own "toughness" on the border. And so, when people hear about the border, they think it *must* be a problem because both parties say so. And so they think "who is stronger on the border?"
They will never think the dems are stronger on the border, no matter how many fascist border policies they adopt. Never.