Like anything, there are pros and cons.

Pro: Tariffs = Money for the government (this could be a con depending on how you think about it).

Pro: Depending on the exact tariff, companies may be more incline to stay in the US. They would have to weigh the decrease in labor and material cost vs. the tariffs imposed to see if they can produce a cheaper product. If they can't, they would stay in the US and those jobs would go to Americans.

Con: By putting tarrifs on products produced overseas, the price would also increase and be closer in line with products currently produced in the US. This means that your corporate brand of a product would be closer to a mom and pop shop brand (More expensive)

Con: With our federal regulations on workplace safety, minimum wage, etc...things would cost a lot more to produce here and consequently a lot more to buy. If iPhones were made in the US, they would cost thousands. If we made a major shift to US manufacturing, many people would not be able to afford their favorite products anymore.

It's a small catch-22. Shifting to US manufacturing means more jobs for Americans but means increased prices all around for those products.