Here is some data going back to at least 1988: https://news.gallup.com/poll/388781/political-party-preferen...
I am stating that the US Republicans do not have the support of "half of the US"; either by half of total population, half of eligable voters, or half of registered voters.
US Independents should have stronger support but that's not really going to put much of a dent in what's iteratively evolved to become a two party bicameral political system thanks to the shortcomings of repeated "First past the post" voting.
What was a bright idea hundreds of years ago hasn't scaled well and converged to unrepresentative gerentopoly.
That certainly comes across as you suggesting that Democrats have broader support. Intentional or not, I found your comment misleading by not incorporating the substantial size of independents.