Illinois is as blue as it gets in the presidential election.  So why would Hillary waste money when she is sure to win?  Serious question.

My guesses: Chicago TV and radio are picked up in Indiana and Wisconsin.  Plus she wants more D votes for Rep. Duckworth for Senate.

The Duckworth connection must be it.  Hadn't thought about that.

TV advertisement is a big pay back to the news media.  Election/political advertisements are a huge source of income for media outlets.   I'm sure the media is concerned about Trump not spending near as much on advertising and is another good reason he is not being supported by media types.  Trump has very little infrastructure/staff compared to typical national canidate.  Trump has scared many that make their living off politics as he is not status quo.  

Always follow the money, the D's have made kick backs and corrupt political pay offs into a science.  I thought the current administration being from Chicago was bad enough and has corrupted the Federal government to new heights.   The Clinton's were selling the Lincoln bedroom when in office and stole the furniture out of the white house when they left.  It'll be like pillage and burn this go around.  Who knows if we'll have a country left in eight years.

Illinois would not be a blue state if the voter turn out wasn't so skewed.  Two counties have huge turn out, bussing people to the polls.  The rest of the state historically has about 20% voter turn out.

People are so disgusted with everyone in this election, that Illinois will probably be blue due to people giving up.

However, there has been a huge surge against Hillary (and for Trump) that she is, and should be, concerned about.  If I was in her shoes I would also spend some money here in Illinois.  If 75% or more of the rest of Illinois turns out to vote, Illinois will most likely NOT be a blue state.

We have all given in to the system and to Chicago-style politics for so long that I am not holding my breath for citizens to all-of-a-sudden become responsible and engaged voters.

ETA:  Just to be accurate, I went back to the numbers.  In presidential elections about 70% of voters turn out state-wide.  In non-presidential elections it's about 50%.  79 counties voted republican, and 23 counties voted democrat in the last presidential election.  It would have been better to say 25% of the state decides the election.

http://www.elections.il.gov/ElectionInformation/ElectionResults.aspx

http://www.elections.il.gov/Downloads/ElectionInformation/VoteTotals/2012GEOfficialVote.pdf

Your Democrat counties:
Alexander
Carroll
Champaign
Cook
DeKalb
DuPage
Fulton
Henderson
henry
Jackson
JoDaviess
Kane
Lake
Mercer
Peoria
Putnam
Rock Island
St Clair
Warren
Whiteside
Will
Winnebago

Alexander, Cook, Jackson, and St Clair counties are consistently Democrat. ( 1,526,815 turn out of 2,949,449 registered voters in 2014 election)

Champaign, Fulton, Henry, Lake, Rock Island, and Whiteside are predominately Democrat. (358,887 turn out of 751,479 registered voters in 2014 election)

3,792,770 people voted in 2014 out of 7,506,073 registered voters. That's 50.5% of people voting.  49.7% of that vote went democrat.  Those people are only 25.1% of the total registered vote.

In the last presidential election (2012), those 4 counties had 2,178,934 of 3,017,398 and those 6 counties had 499,981 of 710,984 turn out.
5,279,752 of 7,520,722 voted in that election.  They accounted for 50.7% of the vote, and they were only 35.6% of the people registered to vote.

Very interesting and spot on information.  Thank you!