I never liked the acronym RINO because it is often simply a misunderstanding of the way legislative majorities are built and a groupthink command which ends up surrendering or abandoning purple districts to the dems. Most RINOs are merely reflections of their purple districts. To expect politicians from purple districts to be thoroughly red is ridiculous. To abandon purple districts to the left because of demands of ideological purity (particularly in this time of Trump who is hardly a traditional conservative) is to dismantle the hard-won majorities we've been able to develop. This nation is now deeply divided, and it is the squishy swing-vote in the center that will decide huge shifts of power. Is now the time to say "Screw you! You're not enough like us!"? No, now is the time to be a big welcoming tent.
Our party needs to win over people in the center and even win over people from the left. But we should NOT do this by moving to the center or becoming lefties. This was Reagan's great genius. As a populist conservative, he won a huge majority not by moving to the center and hoping his right flank would hold, but by moving toward the right and presenting his ideas in a way that was inspiring and attractive to centrists (as solutions and escapes from progressive evils and catastrophes) so that he won over large swaths of people who had voted democrat all their lives but were willing to give him a shot because he made sense, inspired, and exhibited empathy and genuine concern.
Now, having said all this, there are, of course, politicians who are terribly purple even though they come from deeply red districts. These need to be replaced in primaries with redder representatives. Furthermore, there are times when great power redounds to leaders who are moderates and swing-voting representatives because they often break the ties (double entendre intended). But these 'squishes' often become accustomed to and even intoxicated with the power that comes with being a tie-breaker. When they are no longer catered to or courted by their more natural allies, or worse, they lose their powerful posts, they often become bitter to the point of betrayal. Then, if they cannot be reasoned or cajoled back into the fold, they need to be ostracized from the caucus or else they become dangerous double-agents and subversives. There is a cost to this, of course, but the loss of their supporters can be reclaimed with strong campaigns which focuses on winning them (the supporters, not the wayward politician) back.
Meanwhile, we need to receive with open arms all new converts, especially those at whom the rigid ideologues would angrily hurl the label RINO because they were purple rather than the purest of red.