To be clear, no-one knows why Trump vetoed in the first place (his first two excuses were clearly not particularly credible; one could believe them if one liked, of course, but it’s not unreasonable to be sceptical of them). So one is left with speculation. This seems plausible, though obviously no-one can say for sure.
It’s perfectly reasonable to speculate on reasons when someone does something weird, and risky (ultimately, he was overridden) for no obvious reason.
It’s perfectly reasonable to speculate on reasons when someone does something weird, and risky (ultimately, he was overridden) for no obvious reason.