“In the health care battle, there was not an organized effort to bring on board a lot of the conservative grass-roots organizations in support...”

That's because the GOP health care plan was so bad, they had to conceal it and rush a political vote to sneak it through.

Not sure if this tax plan is any better, or maybe Trump thinks his oratory skills are so awesome that people won't care about details.  Of course, his speeches will be aimed at his loyal base. Fortunately, the base won't be voting on the bill.