Counter to narrative, there is/was some US based panel production capacity, we do still make things here! We don't make as many things as in, say, Germany, but there is manufacturing.

The whole reason that these tariffs came in to effect was that some failed manufacturers brought the issue. My understanding is that the manufacturers failed not because it's impossible to do in the US, but simply because of poor management decisions or betting on the wrong technology.

The real question is whether the tariffs will be around long enough to incentivize any new manufacturing capacity in the US. They will almost certainly be slapped down by the WTO in a short amount of time, as previous tariffs like this have been. So by the time anybody could make more manufacturing capacity, it seems likely that the tariffs will no longer be around to support the facility. So new facilities must be planned on the basis of profitability without the tariffs.

Even in this environment, there is new production being planned. However, the jobs associated with this are dwarfed by the number of jobs related to installation of panels. So while this will certainly be a net negative to the US economy in the short term, without much opportunity to provide positive impact.

Basically, just a meaningless PR move by a politician. I don't think it will cause hugely detrimental effects either, it's just stupid.