Reid Wilson reports at The Hill:

The main super-PAC backing Senate Democrats is canceling about two weeks' worth of broadcast TV time in several Ohio markets. The Senate Majority PAC's move is a sign that Democrats are growing increasingly pessimistic about former Gov. Ted Strickland's chances of ousting Sen. Rob Portman (R-Ohio). The group had reserved nearly $4 million in airtime across four Ohio markets between Sept. 6 and Oct. 3. But early Tuesday, several Republican ad buyers told The Hill that at least some of those ads — totaling about $191,000 in the Columbus and Dayton markets set to run between Sept. 6 and Sept. 19 — had been canceled. Another source watching the advertising market said the PAC will delay all of its Ohio advertising until Sept. 20.

The Senate Majority PAC's move comes on the heels of the Democratic Senatorial Campaign Committee's announcement that it would be delaying its Ohio ads.

While Democrats are pulling back, Portman is going up on air with a new TV ad hitting Ted Strickland on coal:

Portman has been running far ahead of Trump: The incumbent Republican senator leads Strickland by 7.5 points in the Real Clear Politics average of Ohio polls, but Trump trails Clinton by 3.8 points.