In the void of policy differences and clear, consistent polling on gubernatorial primary candidates, money is the next best measure.

Spending in the race has soared past $25 million, fueled by two wealthy candidates – Republican Victor Mitchell and Democrat Jared Polis – and a slew of super PACs that have already doled out millions.

Of the more than $20 million spent directly by candidates through the first week of June, Democrats have accounted for about $13.7 million, just over twice the $6.8 million spent by Republicans.

Polis raised more than $10.7 million, including $10.5 million the wealthy congressman has given his own campaign; he spent nearly all of that through the most recent campaign finance reporting deadline.

That’s more than all the candidates combined spent in the last gubernatorial election from start to finish, and there’s no sign Polis is putting the brakes on the expenditures.

By himself, Polis has spent more than the other two leading Democrats – Mike Johnston and Cary Kennedy – and the PACs supporting their campaigns. Among other Democrats, Johnston has raised more than $2.2 million, while Kennedy has raised about $1.9 million.

Polis’ PAC, Bold Colorado, reported raising nearly $300,000 and had spent $250,000 on an ad attacking Kennedy.

Johnston’s PAC, Frontier Fairness, has raised more than $4.3 million. Its donations include $1 million from former New York Mayor Michael Bloomberg, $1 million from LinkedIn founder Reid Hoffman, and $1 million from Connecticut hedge fund manager and charter school backer Stephen Mandel and his wife, Susan.

Kent Thiry, the CEO of Denver-based DaVita who considered running for governor as a Republican, gave Johnston’s PAC $100,000.

The PAC supporting Kennedy, Teachers for Kennedy, took in just shy of $2 million and, according to the PAC, had spent more than $1.4 million on a TV ad and mail campaign attacking Polis and Johnston. Her PAC’s contributions come from teachers unions and liberal donors to an EMILY’s List campaign committee.

Lt. Gov. Donna Lynne, a fourth Democratic candidate, has raised just over $1 million, including about $160,000 she’s donated to her own campaign.

On the GOP side, Mitchell has loaned his campaign $3.9 million and raised only $57,000.

With the help of wealthy family connections, as well as Colorado CEOs and moguls, presumed frontrunner Walker Stapleton has raised $1.6 million, including $475,000 he’s given his campaign. His PAC, Better Colorado Now, has helped keep pace with Mitchell, raising just under $1 million.

Retired investment banker Doug Robinson has raised about $500,000 and loaned his campaign $300,000 on top of that. Build Colorado’s Future, his PAC, has reported nearly $350,000 in donations.

Republican Greg Lopez has raised only about $28,000, loaning his campaign an additional $24,000.

Figures reflect campaign finance reports filed through June 11.