WHAT: California’s largest public- employee union, Service Employees International Union, launched a seven-figure television advertising blitz pressuring GOP legislators to back Gov. Jerry Brown’s tax extensions.

HOW: The ads push hard on public safety worst-case scenarios, warning that another round of budget cuts without more revenue would result in heavy layoffs of police, firefighters and paramedics.

WHY: Democrats need at least two Republican votes in each legislative house to either approve the governor’s tax extensions (SEIU’s preference) or place them on a special-election ballot.