Trump's Tariffs Are Inevitably Going To Backfire, What's His Plan?

So Trump and Co. are going to be placing substantial tariffs on Canada, Mexico and China very soon. I understand that this is being done in aims of motivating an on-shoring of industrial activity, and perhaps it will work. (Then again, given the realities and the system that pushed manufacturing off-shore are still well in place, probably not).

In any case, Trump won the election in large part by promising to lower the cost of living. His tariffs will lead to sharp rises in the prices of various goods. Perhaps you can say he'll get away with this just like anything else, but I don't see how this won't lead to a rejection of the Republican Party by voters come midterm season. What's the idea here?