Mr. Trump might consider that his silence is doing damage to more than simply himself. Across the country, Republican candidates are facing voters angry about health care. It would help immensely if they could argue that repealing ObamaCare would be the pressing priority of a Trump administration. After years of having President Obama halt every GOP attempt to patch the law’s holes, this is an extraordinary moment in which the party can tantalize voters with the hope that the nightmare might end.

But to do that, Mr. Trump has to capitalize on one of the greatest political gifts any presidential candidate has ever been given.

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