Nate Silver‘s latest forecast has the odds of Democrats retining control of the U.S. Senate after November’s election — either by having at least 50 seats and the presidency, or 51 without it — have increased in recent weeks to a 70% chance.
“The trend toward Democrats is a relatively recent one. Part of the shift may reflect the bounce President Obama received from the Democratic convention… But our analysis also suggests that the Democratic advantage has probably been building over the past few weeks, and may not have any one root cause. Instead, Republicans risk death by a thousand cuts, with a gradual deterioration in their standing in several important races, and their inability to field optimal candidates in others.”