Scott Jennings, a CNN contributor, is a former special assistant to President George W. Bush and former campaign adviser to Sen. Mitch McConnell. He is a partner at RunSwitch Public Relations in Louisville, Kentucky. Follow him on Twitter @ScottJenningsKY. The opinions expressed in this commentary are his own.

(CNN) A great many Republicans have had their differences with Arizona Sen. John McCain over the years, and some of President Donald Trump's biggest supporters are using the occasion of the release of the senator's memoir to bash McCain in the sunset of his career and life.

Scott Jennings

They take to Twitter to bash a guy who suffered torture for his country, lived a life of public service and consequence, and has the audacity to express his political opinions and preferences on who eulogizes him.

You don't have to love John McCain to know this is wrong and, as Jonah Goldberg put it, "grotesque."

It is true that those of us who supported George W. Bush over McCain in the 2000 GOP primary found his attacks against Bush to be whiny and irritating. McCain's position and vitriolic statements on campaign finance "reform" were grating, especially when you consider that his legislation did the opposite of reforming the system. It drove money out of the hands of candidates and parties, and into the shadows of outside groups.

McCain's legacy on campaign finance, well-meaning as it may have been, is a broken system that he helped to drive fully off the rails.

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