Control of the Senate less certain than ever?

According to MSNBC, control of the Senate is less certain than ever:

As November approaches, control of the Senate is growing increasingly unpredictable as Republican gains in key states are offset by new vulnerabilities in unexpected places.

The good news for Republicans is that they???re increasingly well positioned to win the races they identified as most crucial to securing a Senate majority at the start of the cycle.

In the four states Mitt Romney won where Democratic incumbents are on the ballot, Republican challengers are leading recent polls in three: Alaska, Arkansas, and Louisiana. The exception is North Carolina, where Sen. Kay Hagan has opened up a small lead over challenger Thom Tillis.

At the start of the cycle, Republicans might have assumed that would be enough to win a majority. They need six seats to take over the Senate and went into 2014 heavily favored to win seats in South Dakota, Montana, and West Virginia opened up by Democratic retirements.

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