Rich Miller: So why is Sam McCann running for governor?

Several months ago, Michael Madigan's chief of staff Tim Mapes made copies of candidate nominating petitions for what appeared to be every single candidate in the state, regardless of party or office.

It turns out that a database was constructed of the names of all the petition circulators who worked the primary.

State Sen. Sam McCann (R-Plainview) pulled the trigger last week on a third-party bid for governor. The avowed foe of Gov. Bruce Rauner will need to collect 25,000 valid petition signatures by June 25 to get onto the November ballot.

However, under state law, all signatures gathered by people who circulated petitions for partisan primary candidates will be invalidated.

So, it is now a relatively simple matter of plugging in names of potential petition circulators into the new database in order to weed out problems.

If McCann gets on the ballot, the idea here is to establish a new party's identity with one specific goal in mind. Its name is the Conservative Party, and its mission is to attract conservative Republican voters who are upset at Rauner on abortion, "sanctuary state" and possibly guns.

Four years ago, Operating Engineers Union Local 150 backed the Libertarian Party's candidate to hurt Rauner, but that candidate also got votes from folks who didn't like Gov. Pat Quinn.

If McCann survives the petition process, one challenge will be finding money for this race.

Lots of union leaders and others believe the billionaire J.B. Pritzker has this race in the bag; that Pritzker's personal fortune along with a strong national wave will destroy the Republican incumbent.

But folks behind the Conservative Party (including Local 150) believe they need a Plan B in case something goes wrong.

Pritzker could be hit with some unforeseen opposition research, for example. The national political climate could suddenly change for any number of reasons. Rauner could somehow get his act together.

And even if the Democrats' stars remain aligned all the way through November, a McCann candidacy could help the Democrats run up the score.

The plan has its detractors. Democratic legislative candidates in Republican-leaning districts are hoping that the national "blue wave" so many see heading this way, combined with Gov. Rauner's unpopularity, will lead to lower turnout among Republicans and help them squeak through.

Putting McCann on the ticket gives disaffected Republican voters a reason to head to the polls. They won't be voting for Democrats down the ballot.

A top Republican official with close ties to the governor said Sen. McCann could attract some Democratic votes as well.

J.B. Pritzker, after all, has far more liberal stances than Rauner on immigration, guns, abortion, etc. Rauner has repeatedly said in recent weeks that he strongly opposes illegal immigration and flatly denies that a bill he signed into law created a "sanctuary state."

The governor also claims to be an NRA member and vetoed a bill last month that would've regulated gun dealers. Pritzker's vast holdings include several companies that have really bad records when it comes to their employees.

In other words, it's conceivable that the Rauner campaign could use targeted media to try and drive conservative, pro-union Democrats and independents to McCann.

It's also very possible that Rauner will go all-out negative against McCann. A far-right group aired a nasty radio ad during the March primary about Rauner and his wife. The Rauner folks may feel free to go just as negative on McCann.

Operating Engineers Union Local 150 contributed $50,000 to McCann's campaign a few days before his announcement. The union is known for unorthodox political moves, like working with conservative activist Dan Proft during the primary against House Republican Leader Jim Durkin.

But the involvement of 150 gives Rauner the ability to use the "Madigan issue" against McCann because the union local has close ties to the House Speaker.

If you thought the weirdness ended on primary day, it's actually just beginning.

Rich Miller also publishes Capitol Fax, a daily political newsletter, and CapitolFax.com.