Gov. Arnold Schwarzenegger griped last year that the state prison guards union had grown too powerful. So who did he appoint to challenge the labor group during contract talks this spring? A former guard who helped engineer the union's rise to prominence. Tim Virga, a one-time union activist, will act as one of the state's lead negotiators in talks with the California Correctional Peace Officers Association. State officials this week described Virga as a skilled negotiator who will drive a tough bargain with the 30,000-member union, widely considered one of California's most politically influential labor groups. “Mr. Virga's background and...