Bos has two daughters, with a third due in January. At the grocery store, five items cost as much as a full cart once did. And on Wednesday, Bos and nearly 1,400 other people were laid off from their jobs at what had been the Navistar truck factory in southwestern Ohio.
Asked how many times he had voted for Trump, Bos held up three tattooed fingers. But he said he’s done with the president.
https://dictionary.cambridge.org/dictionary/english/could#cald4-1-4
You used the whole thing in past tense, as if the event already happened, not future tense.
What you wanted to say was “Trump did what the Democrats never could; make it very likely for a Texas Democrat to be elected to the Senate.”
By saying “put” you implied the event already came to pass.
English is a dumb language though so understandable for your mistake to be made.
The “could” earlier in the sentence applies to the phrase beginning with “put”. The grammar is fine, though the sentence is a little long.