There's now room for error, with Phil Breseden in Tennessee and Beto O'Rourke in Texas making two more Democratic pickups in play.
NBC News released a poll of Tennesseeconducted with Marist on Thursday, and Democratic Senate candidate Phil Bredesen has a statistically insignificant 2 percentage point lead over Republican Rep. Marsha Blackburn among likely voters. Among all registered voters, Bredesesn's lead expands to 4 points, 48 percent to 44 percent. Both results are within the poll's margin of error (±4.5 points for registered voters, ±5.5 points for likely voters), but combined with NBC/Marist polls this week from Indiana and Missouri, they suggest Democrats have a shot at winning control of the Senate in November, despite an unfavorable map.
Bredesen, a popular former governor, and Blackburn are running to succeed Sen. Bob Corker (R-Tenn.). Democrats, meanwhile, are defending Senate seats in Missouri, Indiana, North Dakota, Missouri, Florida, West Virginia, Wisconsin, Ohio, and other states President Trump won in 2016. They need a net gain of two seats to win control, and their best shots of flipping seats are Arizona and Nevada.
In NBC/Marist's poll of Indiana released Wednesday, Sen. Joe Donnelly (D) leads GOP challenger Mike Braun 49 percent to 43 percent among likely voters, just outside the poll's ±5 point margin of error. In Missouri, Tuesday's NBC/Marist poll found Sen. Claire McCaskill (D) and state Attorney General Josh Hawley (R) tied in a two-way race, 47 percent each, and McCaskill takes a 4-point lead if Libertarian and Green candidates are included. All three polls were conducted Aug. 25-29. Political handicapper Stuart Rothenberg, looking at those polls and others in Florida, West Virginia, and elsewhere, sees new hope for the Democrats.
Of course, at this point in 2016, Hillary Clinton had 1 70% chance of winning too, which is about what Democrats have of winning the House back.
There's still plenty of time for things to go wrong, and Democrats cannot forget that.