Here’s irony for you: The June 6 primary at which voters will decide which Democrat will face Arnold Schwarzenegger in the fall could be preceded by such a vicious slugfest between eBay multimillionaire and now-state Controller Steve Westly, and longtime party hack and now-state Treasurer Phil Angelides that these two guys accidentally send voters back into Arnold’s arms.

A fresh poll from the Public Policy Institute of California (PPIC) shows Schwarzenegger’s approval ratings up 8 percentage points among likely voters over his abysmal bottoming-out last fall — an uptick that’s in line with other polls.

For example, in a survey of 757 registered voters by the Survey and Policy Research Institute at San Jose State University two weeks ago, the Governor’s approval rating was at 40 percent. The rating in their prior poll in September was 36 percent.

Somebody finally figured out that Arnold needs to govern without a smirk and needs to govern as the centrist he actually is. Every week that Schwarzenegger pursues responsible stuff like fixing the state’s infrastructure means another potential upward tick in his approval ratings.

Mark Baldassare, director of research at PPIC, tells me that the governor is being helped by “attitudes about the economy picking up in California.”

Baldassare also suspects that voters feel better about Schwarzenegger because “all the millions of dollars spent dragging his name through the mud during the special election stopped — and stopped having an effect. The governor began to get his message out.”

Arnold was badly, badly hurt not just by his errors but also by vast sums spent directly attacking him during the November special election. That negative campaign lesson is hardly lost on Westly and Angelides, only one of whom can remain standing after June 6.

I expect them both to go negative against one another, big-time. It’s no coincidence that the likable and moderate eBay multimillionaire Westly has hired onto his campaign “South the Mouth” — the outrageous former advisor to Gray Davis whose bombast didn’t do Davis any favors.

And it’s no coincidence that the dour and much further left Angelides has hired onto his campaign Bob Mulholland — the bizarre flamethrower who for years has been the embarrassing spokesman for the state Democratic Party.

These two gents — South and Mulholland — are practitioners of the unfettered slugfest. It’s not clear if Mulholland, who is all bombast, all the time, is good at anything else. South at least demonstrates serious knowledge of issues facing California, yet he seems to squeeze them in between his long periods of bombast.

Shall we talk examples?

Not long ago, South told one Los Angeles newspaper that Angelides is essentially an “insufferable know-it-all.” He also told one Sacramento paper that “Angelides has been shrill and strident and has moved way too far to the left. … And if he is the nominee, the [Republicans] will slice him and dice him like a Veg-O-Matic.”

South hardly limits his mouthy dialogue to Westly. According to one political columnist, South recently claimed that private focus groups conducted by the Westly campaign (to test the waters among conservative Democrats and centrist independents) described Gov. Schwarzenegger as a “dumb actor, bad actor, political actor, fool, clown, egoist, bozo, liar” and much more.

Mulholland is even worse when it comes to lowering the level of political discourse. But where South clearly displays a methodical, carefully chosen — if offensive — attack strategy, Mulholland often sounds out of control, incomprehensible, and almost creepily negative.

For example, back in November during the special election, Mulholland gave an interview to KNTV-NBC 11 in which he got so frothy about the mouth that he accused the governor of being “not a man.”

It was such a weird, icky — but typical — comment from the longtime Democratic Party spokesman that embarrassed Senate President Pro Tem Don Perata — one of the good-guy Democrats in Sacramento — barked back that Mulholland “ought to shut up.”

If anything, South and Mulholland will get much meaner now that they are attacking fellow Democrats because that’s just how internecine war works. And Angelides not only has the albatross of using Mulholland as a senior advisor, but he’s also got a big psychological chip on his shoulder toward Westly.

It’s got to drive Angelides crazy that, after plugging away in obscurity for years, doing his party’s bidding, showing up at endless and boring party state conventions, gladhanding lobbyists and hangers-on all these years, Westly has breezed into Sacramento and, with little effort shown early promise as a gubernatorial candidate against Schwarzenegger.

In one of the many “horse race” match-ups of fantasy candidates that we are bound to see this year, the still-unpopular Schwarzenegger in mid-January led Angelides 41 percent to 39 percent in this largely Democratic state. At the same time, however, Westly came out slightly ahead of Schwarzenegger, 40 percent to 39 percent.

Baldassare warns that “I don’t put much stake in these kinds of test match-ups,” because so much can change by the time the two real candidates face one another. But still.

The real goal of these two right-hand men to the leading Democratic candidates is the same: to help their guy bring down Arnold next November. But even in a mostly Democratic state like California, it is possible to emerge from such a primary contest so bloodied that your own family, er, party, won’t claim you.

It’s pretty easy to predict that the loyal lefty party hack Angelides will win the lion’s share of endorsements and money from Democratic Party institutions like the California Teachers Association. In fact, the CTA, which has surprisingly little sway given the huge fortunes of $10 million to $50 million that it spends during election season in California, just endorsed Angelides a few days ago.

Woo hoo. Big endorsements and lots of big money from traditional Democratic institutions were of no help at all in 2003, when the party showered its favors on a similar loyal lefty hack named Cruz Bustamante.

Even with all of the money and many of the key endorsements going to Angelides, I still suspect the June 6 primary will be Westly’s to lose.

The camera is kind to the upbeat and attractive Westly and downright nasty to the dour and rawly over-ambitious Angelides. Westly is pragmatic; Angelides is histrionic. The self-made Internet multimillionaire Westly has the luxury of writing his own personal checks to finance his race. But the well-off yet not as rich former developer Angelides must beg from and make promises to every special interest between here and the border.

On Angelides’ side of the ledger, the June 6 primary is going to be a very low-turnout election, since the only interesting ballot initiative is Rob Reiner’s bid to fund free preschool for all California children regardless of family income level.

Whenever there’s a low-turnout primary this dull, the result is that California’s armchair Democrats — the people who don’t vote every single time — tend to stay home. The Dems who do vote in such primaries tend to be either drooling loyalist types or older folks who are more strongly committed to the voting process itself. (The same holds true during low-turnout Republican primaries — drooling loyalists and old folks dominate at the polls.)

Angelides will win among drooling loyalists because he is much further to the left than Westly (he backs driver’s licenses for illegal aliens and so on).

However, Angelides is running as Cruz Bustamante-lite, if such a thing is possible, by pushing a dreary version of the disastrous 2003 Bustamante campaign platform: far higher taxes on Californians to pay for pet plans.

If Democratic voters learned anything from Bustamante’s trouncing in the recall, it’s that you don’t make a big play for power in a state like California by trotting out the party’s also-rans. Voters will probably see Westly as the clearer threat to Arnold.

If so, the trick for Westly will be to win the primary without getting so bloodied that the voters decide to stick with Arnold, whose approval rating among both independents and Democrats is improving.

Baldassare, ever the understated pollster, tells me, “It’s not a good situation for the Democrats, to have two candidates finding fault with one another for the next six months while the governor stays out of it and works on infrastructure.”

No. Not long ago, Art Torres, leader of the California Democratic Party, told a reporter he held out great hope that the two Democratic candidates would keep things positive and upbeat for as long as possible. That should last for about five minutes.

Nevertheless, Torres may be peddling at least a seed of truth. In this contest to decide who faces Arnold, it will come down to which guy’s bombastic advisor — South or Mulholland — helps their candidate avoids the slugfest long enough to address daunting issues that will face California long after the June 6 struggle is over.