What is a Republican and what is a RINO? What percent of Republicans in congress are RINOs?

I’ve heard a lot of Republicans be labelled “RINOs” by Trump supporters – from former Presidential candidates such as McCain and Romney to prominent congressional leaders such as McConnell and McCarty. It almost seems like a majority of Republican politicians these days are republicans in name only – do you think that’s the case? Also:

• Are there specific political positions you look at to identify RINOs?

• If RINOs are a minority, how have they gained and maintained so much power in the party? If they are the majority, wouldn’t it be more accurate to characterize their Republican detractors as RINOs?