The RINO is an interesting political phenomenon and relatively new.  It stands for Republican in Name Only, meaning that although the office-holder is a registered Republican, his voting record and public statements are too often aligned with liberal causes.

Charlie Baker, the current governor of Massachusetts, is a classic example of the RINO.  He openly and proudly supports the Bathroom Bill (a Mass. ballot question that will allow any person of any sex or "gender identity" to use any public bathroom he chooses); refuses to come out strongly against sanctuary cities; and will not champion the rollback of Massachusetts's onerous state sales tax, which was raised by preceding Democratic Governor Deval Patrick from 5% to 6.25% – an astonishing 25% increase.  In fact, Baker's overall policy approach and his stances on traditional Republican-conservative issues are so left-leaning that he has earned the derisive sobriquet of "Tall Deval" – a reference to his 6-ft., 5-in. height and his liberal governing philosophy.  That his approval rating is so high in heavily Democratic Massachusetts that he is called "The Most Popular Governor in the Country" says it all.  He is, indeed, the prototypical RINO.

This kind of politician seems to exist only on the Republican side of the fence.  Only Republicans have to scramble to make sure all their members are on board for crucial congressional votes.  When a Senate vote looms on a controversial measure, only Republicans have to be certain that all their members are on the same page.  John McCain was famous for deviating from Republican orthodoxy, earning him the positive-intentioned nickname from the liberal mainstream media of "Maverick of the Senate."  There are many Republican politicians who are famous for their voting or public speaking "undependability," such as Lisa Murkowski (Alaska), Jeff Flake (Ariz.), Rand Paul (Ky.), Lindsey Graham (S.C.), and Susan Collins (Maine), and, before her, Olympia Snowe (Maine).  With the Senate as closely divided between the parties as it's been in recent years, a few perfidious Republican senators are all it takes to defeat a conservative initiative.

The reverse is not true on the Democratic side.  There are no DINOs.  Rarely will a Democratic senator speak out against his party's approved position or threaten to vote with the opposition.  If a Democrat votes with the Republican position, it's almost always when the measure would have passed anyway and the Democrat in question has been given the behind-doors "nod-nod, wink-wink authorization" that it's okay with the Democratic hierarchy if he votes against the party in order to preserve his popularity with his local electorate.  A Joe Manchin (W.Va.), for example, may vote with the Republicans occasionally, but only when it's "safe" to do so.  When was the last time Joe Manchin was the deciding conservative vote on a truly contentious issue, the way Republican McCain was when he sided with the liberals on the Obamacare repeal vote?  It just doesn't happen that way.

Those are the facts.  That's the way things actually are.  There are RINOs but no DINOs.  The question is, why?  Is there something inherent in the liberal and conservative mindsets that predetermines a proclivity to deviating from party convention?

This is where it gets interesting, because any answer to this question is pure, unprovable conjecture.  Conservatives will say this: by their nature, conservatives are more emotionally and intellectually honest, more no-nonsense than liberals, per the old cliché, "conservatives think, but liberals feel."  Conservatives simply look at how things are and act accordingly.  They have an inherent, fundamental belief in the ability of the individual to determine his own fate and make his own choices, as opposed to the State being better able to control and determine the direction of an individual's life.  If this belief in the individual sometimes leads a rogue Republican to deviate from the party line, then that's simply the price that must be paid for adhering to the precept of individual responsibility and opportunity.  Being faithful to one's conscience and value system will require actions that are politically inconvenient – even counterproductive – on occasion.

Conservatives think liberals are fundamentally disingenuous, far too frequently in service to Democratic political goals.  By dividing the electorate into racial, sex-based, and social subgroups (like women, minorities, immigrants, gays and transgenders, low-income, etc.) and then convincing each group of its victimhood status at the hands of Republicans, Democrats orient their election strategy around the concept of relieving these groups' grievances via tax-funded government policies.

• "You're poor because of Republicans – vote for us, and we'll change that."
• "You're not welcome in this country because of Republicans – vote for us, and we'll change that."
• "You can't advance at work because of Republicans – vote for us, and we'll change that."

Then, in order for Democrats to win their elections, the victim groups must remain victimized so the Democrats can continue to come to their "rescue" with yet another tax-funded government program.  If any of these groups is successful, it no longer needs the Democrats' help, so it's in the Democrats' interest that these victim groups remain disadvantaged.  Staying together in party unity on major votes to continue or introduce new targeted tax-funded government programs is a simple matter of job preservation for the Democrats.  That's how conservatives see it.

Conservatives see themselves as being more concerned with the big picture, the country as a whole, rather than individual racial, demographic, or ethnic groups.  Conservatives think policies that lead to a good economy or strong national security or energy independence (free of undue OPEC influence) redounds to the benefit of all Americans, in every group, both sexes, every ethnicity.  Thus, given their concern for the big picture, it's understandable that there may be an independent-thinking RINO here and there, because conservatives are not looking at job preservation the same way liberals are.

Liberals simply feel that their positions are incontrovertibly correct, therefore there will never be a DINO because there is no need.  In their view, RINOs happen in those rare instances when a Republican has a moment of clarity.

The fact remains: "RINO" is a well accepted term in the popular political lexicon.  The term "DINO" doesn't exist.  Draw your own conclusions.