Re: Not what they say, what they do
"Like most Republican leaders Trump is utterly convinced of the dangers of climate change"
No, you're wrong in your assumptions about Trump, and only a handful of Republo-Crats have actually swallowed the koolaid on man-made-<whiny-voice>ClimateChange</whiny-voice>
Trump said he had an "open mind". I know that global-warming-fascist types assume that means "swallows their propaganda and asks for another" but his governance obviously says the opposite. Top 10 results in an online search confirm this.
And why do you assume that "fusion experiments in space" mean shipping ITER there? I think your vision on what is possible may be a bit too narrow. In space, you can cross multiple proton beams without containment, as one possible research example. The biggest problem with fusion (in my opinion) is the containment. The second is the confinement. Eliminating containment problems gives you more options for researching how to do the confinement better, and a LOT of things have probably NOT been tried, and don't require "what you said" to be launched into orbit.
Anyway, that's just ONE thing that space helps with.
I'm also looking forward to a 2001-like space station, with multiple gravity levels for various purposes.
But yeah you have to think out of the box for some of this stuff. being stuck in the mindset of what everyone else is doing at the moment doesn't give you a whole lot of freedom for how to do things.