With California's Primary just a day away, some voters are getting messages that might make them think twice.  In some races, unions are urging Democrats to vote for Republicans.  In others, business groups are urging Republicans to vote for Democrats.  It's a change in political strategy inspired by California's new "Top-Two" primary.

Business Groups Target Democratic Districts

Then, there's this radio ad airing in parts of the Central Valley:

Radio ad: "He put himself through college, and he's been serving the community ever since - leading efforts to protect farmers from excessive taxes and safeguard homeowners from loan fraud."

Protecting farmers from excessive taxes - a campaign ad you'd think would be for a Republican.  But it's for a Democrat.

Radio ad: "Adam Gray - Central Valley values for State Assembly.  Paid for by JobsPAC, a bipartisan coalition of California employers."

Both ads are paid for by JobsPAC - a political action committee led by the California Chamber of Commerce.  They represent a new strategy in the state's changed political climate.  Longtime GOP strategist Marty Wilson is running the Chamber's effort.  He says the new combination of the "Top-Two" primary and independently-drawn legislative districts has created far more competitive races - particularly for State Assembly.  So…

Wilson: "There's a lot of opportunity for us to go in and look at the Top-Two primary process and see if there's a means by which we can get Democrats to vote for Republicans or Republicans to vote for Democrats." (0:12)

Before this year, that was never possible in a Primary.  But now, under the "Top Two" system, a voter of any party - or a registered independent - can vote for a candidate in any party.  Wilson says the goal is to find more pragmatic candidates.  Others might use the word "moderate."

Wilson: "We're looking for somebody who has the attitude that they're going to be here to solve problems and not climb up on some ideological soapbox and proclaim their views to the world, which is really not very productive."

Unions Spend Big in Republican Districts

The Chamber isn't alone in adapting to the new system.  The Service Employees International Union, which declined an opportunity to comment on this story, is spending big to convince some Democrats to vote for Republicans.  Take, for example, an Assembly race along the Orange County coastline.  GOP Assemblyman Allan Mansoor faces a challenge from another Republican.  Mansoor has signed a no-tax pledge.  His challenger has not.  Mansoor says he's been the target of "hit pieces."

Mansoor: "There's been a variety of pieces.  You have independent expenditure committees sending out a ton of mail in support of my opponent and attacking me."

Like this one, that says: "During the state budget crisis, Allan Mansoor gave his Capitol staff a raise."  That mailer comes from a group of health professionals and unions called "Californians for Fiscal Accountability."  Tea Party Assemblyman Tim Donnelly, who also faces a GOP challenger, says he's been the target of similar mailers:

Donnelly: "When you can bring forces like that, you can literally sway an election.  And the people of my district like me.  The unions hate my guts.  So they've sent eight mail pieces.  Eight mail pieces!"

Hoffenblum: "Now, all they have to do is be in the top two, and they better have the money ready to be able to be competitive in the election of consequence."

Hoffenblum says as many as 23 Assembly races and four State Senate runoffs could feature two candidates from the same party.  Democrats are currently two votes shy in each house of the two-thirds supermajority needed to raise taxes or send initiatives to voters.