The GOP isn't rigging it now, even outright cancelling primaries in some States to not risk Trump winning next year?
The gridlock is for supposed Democrat proposals that never seem to ever go anywhere because they're too busy being so incredibly 'worried about upcoming elections.' The Do-Nothing Congress was honest in its mission to do nothing but screw Obama.
With Republican initiatives, the Dems have a delightful habit of going along for the sake of 'civility.' Nancy 'But I Don't Wanna Impeach Him Now' Pelosi, Chuck 'Got Congress By the Balls Over DACA WIth The Gov't Shutdown But Let's Leave It For Some Other Time' Schumer, Bill 'Don't Twist My Arm, I'll Sign It' Clinton... Heck, the Dems offered Trump $1.65 billion for the Mexican Wall, Repubs offered him $0.
The GOP is not going along with Trump, he's going along with them. They're using him. He's that simple minded doofus in hs that his classmates use because he's got a rich daddy.
Other politicians have reelections, legacies, and a general dislike of prison time to consider. Trump is the Golden Goose - an impulsive narcissistic megalomaniac with no concern other than today's Happy Meal toy. He'll take the risks they won't because he has no concept of tomorrow. Massive tax cuts for the wealthy, deregulations, flagrantly sidestepping gov't intitutions and law, consolidatng power of the Presidency... They throw the base some candy - anti-abortion, no trannies in the Military to tempt their sons... and they lap the rest up like dutiful hound dogs.