There are lots of reasons that Democrat Terry McAuliffe is poised to beat state Attorney General Ken Cuccinelli in the Virginia governor's race on Tuesday. But, none is more important -- or, perhaps, undertold -- than McAuliffe's massive fundraising advantage over the Republican nominee.

As of Oct. 23, McAuliffe had raised north of $34 million while Cuccinelli had brought in just $19 million. By comparison, Republican Bob McDonnell had raised $21 million at this time in the 2009 race while Democrat Creigh Deeds had collected $16 million.  (McDonnell won with 59 percent.) McAuliffe's almost two-to-one fundraising lead translates into one very important thing: lots and lots more ads.

Check out this chart, put together by The Atlas Project, a Democratic group, using ad buying data from Kantar Media/CMAG, detailing how many television ads the two candidates in the 2013 and 2009 governors' race ran in the weeks running up to election day.

Image courtesy of The Atlas Project

A few interesting notes on the chart:

* The ad wars in 2013 began a month earlier than they did in 2009.

* Cuccinelli was able to stay within shouting distance of McAuliffe on TV through Labor Day. But, as polls began to show the Democrat with an edge, Cuccinelli's fundraising -- and therefore his ability to buy ad time -- dropped precipitously.

* In the critical final month of the race, McAuliffe's financial edge grew wider and wider. Take the week of October 21 as an example. McAuliffe was running nearly 3,000 TV ads while Cuccinelli was on air with less than 1,500 ads.  Compare that to the ad spending in the 2009 race over the final weeks when McDonnell running ad circles around Deeds.

There will be lots and lots of after-action analysis about what a McAuliffe victory -- if it happens -- means for the two parties' national prospects.  And, there are no doubt lessons to be learned. But the key lesson is that the candidate with the most money usually wins.