“Free trade” means letting everyone do what they’re best at and then exchange the goods they produce. This is so that everybody is focused on what works best in their country, everything is done as well and as cheaply as possible. However this makes no guarantee about any one country’s ability, at the end of the day, to stand alone without dependencies on others for vital goods. In fact if anything it works against that.
I don’t know why Trump talks about globalism as some Democrat thing. It’s his own party that has been driving for free trade since forever.