"Evil" is defined in Wikipedia thus: 1) Evil generally seeks own [sic] benefit at the expense of others and is based on general malevolence and 2) any particular individual or [political entity] which may follow these forces or behaviors.
I herein maintain that a political party (or sub-set thereof), which, when possessed of sufficient political influence to effect actions which accrue to the benefit of itself and its benefactors to the clear and present detriment of others, is inherently malevolent. I would also maintain that being forced to pay a fair and reasonable level of taxes is not detrimental to any individual or organization in the sense intended in the context of this definition.
Therefore, a political party which consistently pursues positions which 1) seek to deny any group of citizens access to their full constitutional rights through withholding funds or redefining terms or following a course of "death by a thousand cuts" in an attempt to pacify a zealous portion of their political base; 2) manufacture a financial crisis so as to provide the political cover for undermining the well-being of a class of citizens which does not vote "as they should"; 3) seek to thwart every policy position of a president in the hope that it will make him (or her) look bad and help their own political cause; 4) ceaselessly berate our government and its employees in the attempt to deny it the popular confidence needed to effectively govern; 5) denigrate a nearly unanimously-held scientific theory which, if allowed to progress to its logical conclusion without human intervention, would mean the end of life as we know it simply because the alternative is to deny certain industries (which contribute financially to that party's coffers) future profits; 6) focus on reversing decades of human progress rather than finding solutions to real problems; 7) consider any and all solutions to common human problems that don't originate with domestic capitalists as worthless; 8) refuse any reasonable effort to address the questions of racism, religious persecution, homophobia, poverty, hunger, or poor health on the false grounds that they are either nonexistent or beyond our means; 9) derive from the principle that the more capital that is held by the fewest number, the better for everyone; and 10) pretend that 25% of its base is not so uninformed and naive as to risk dragging the country into a mindless, immoral morass of senseless-but-well-armed blabber is an evil institution.
It has taken me six-and-one half decades to reach this rather extreme position. Still, the Republican Party of today is such a far cry from that of President Eisenhower that I have trouble getting my mind around it. The political revolution that started with Ronald Reagan has brought us to the point where neither he nor Sen. Barry Goldwater could likely run for office today without having to worry about in intra-party battle with a primary challenger from the Right. This, with none of the social, economic, and political upheaval that let to Germany's slide into fascism in the 1920's and 30's. Yet, we now have state legislators who advocate making it legal to murder abortion providers. Others want to force everybody to carry a firearm, deny health care to poor women and children (perhaps, the "soft genocide" of economic conservatism), and denying the EPA the power to regulate greenhouse gases. When a person, motivated by the promise or actuality of economic gain, acts in furtherance of a design which would inevitably lead to the death of someone (perhaps thousands), we might call that accessory before the fact to involuntary manslaughter. I would prefer to simply call it "EVIL".