I agree that the 'subject clause' makes that amendment absolutely clear, but Scotus decided nonetheless that it meant anyone born here. It is an irrational interpretation, and in my opinion a criminal one.
Nonetheless, it needs to be stopped, and an addition to the amendment is the most certain answer. "All persons born to a US citizen or naturalized in the United States, and subject to the jurisdiction thereof..."
Congress has both the power and authority to pass legislation to enforce the 14th Amendment. If Congress determines that Illegal Aliens, by trespassing on the territory of the United States, are not “subject to the Jurisdiction of the United States, then their children born during the trespass would not be eligible for birthright citzenship. The power to control the immigration laws is given to Congress and not the courts. The 14th amendment was not passed to give trespassers the same rights as legal residents. There is nothing in the history of the 14th Amendment which could possibly be construed to suggest that was the intent.