Republican on Republican primary violence!

Roberson, R-Henderson, represents a seat that’s up for grabs in the 2014 election — its voter registration is almost evenly split between Republicans and Democrats. But as the Review-Journal’s Laura Myers reported this weekend, before Roberson can face a Democratic challenger he’ll have to win a GOP primary battle against Carl Bunce.

Regular readers will remember Bunce’s name — he’s one of the long-suffering, hardworking followers of former Texas Rep. Ron Paul. Bunce and some like-minded conservatives helped take over the Clark County Republican Party and the state Republican Party in 2012, creating a rift that caused GOP presidential nominee Mitt Romney and establishment-type Republicans to take their ball and form their own shadow party.

We all know how that worked out.

Now Bunce has left his position with the Clark County Republican Party to take on Roberson. (As an added bonus, Bunce’s brother, Richard, will challenge Assemblyman Lynn Stewart, R-Henderson. Registered Republican voters outnumber Democrats by about 2,000 in that district.)

Roberson has been targeted by the Ron Paul/libertarian wing of the party because of a dramatic shift in some of his views from the 2011 session to today. In 2011, he was named “Rookie of the Year” by the conservative group Citizen Outreach. This year, he was given the organization’s “Rat Head in a Coke Bottle” dishonor for allegedly tarnishing the Republican brand.

Roberson has embraced some tax increases: After voting against the state budget in 2011 despite Republican Gov. Brian Sandoval’s support for an extension of tax rates that had been scheduled to expire, Roberson reversed course in 2013 and voted for a budget that included new extensions of those same tax rates. Roberson also was the champion of a joint resolution that next year will give voters the opportunity to remove the state constitution’s cap on mining taxes.

But don’t think Roberson has gone totally liberal. He promoted the mining tax as an alternative to a 2 percent margins tax that will appear on the 2014 ballot, a tax vehemently opposed by business. He wanted a mining tax plan to appear alongside the margins tax next year, in the hopes of killing the business levy.

When Senate Majority Leader Mo Denis, D-Las Vegas, proposed increasing the payroll tax, it was Roberson who mocked him on the Senate floor. (Denis withdrew the idea.) When Assembly Speaker Marilyn Kirkpatrick introduced a bill that would have levied a tax on movie theater tickets, bowling games and going to the gym, it was Roberson who derided it as the “Family Fun Tax.” That proposal also failed.

And Roberson voted against a bill that would have extended currently required background checks on gun sales to private-party gun sales, after introducing an alternative gun bill without the checks.

A liberal he’s not. But he is willing to compromise on some things, and in the rift-ridden modern GOP, that’s forbidden, since compromise cannot help but lead to the erosion of conservative principle.

Democrats, it must be said, don’t really have this problem. That’s not to say they lack philosophical diversity or true believers: Put U.S. Sen. Bernie Sanders, I-Vt., up against President Barack Obama on health care, for example, or look at the difference of opinion on the NSA spying program between, say, Rep. John Conyers, D-Mich., and Rep. Nancy Pelosi, D-Calif. It’s just that Democrats generally have learned to suck up those differences without civil wars that rend their party.

Not so the GOP, which is why Roberson (and Stewart) will have to run two races next year to win re-election, one against conservatives and another against Democrats.

Working very well together? Ask Roberson how that’s working out.

Steve Sebelius is a Las Vegas Review-Journal political columnist and author of the blog SlashPolitics.com. Follow him on Twitter (@SteveSebelius) or reach him at (702) 387-5276 or ssebelius@ reviewjournal.com.