When Democrats lost control of the U.S. Senate in 2014, many on the left consoled themselves with the notion that this condition was merely temporary. The 2016 Senate landscape, they said, heavily favors Democratic candidates and Republicans are likely to be only temporary custodians of the upper chamber.

In making this claim, Democrats say that several Republican Senators who won seats in traditionally blue states in the 2010 midterms are going to have a rough time keeping them when a presidential electorate turns out in 2016. Many speculate that the most vulnerable Republicans in the Senate will be Sens. Mark Kirk (R-IL), Ron Johnson (R-WI), and Pat Toomey (R-PA).

But Democrats will not find any of these Republicans to be pushovers. Kirk, a moderate Republican and a good fit for the Illinois electorate, continues to recover from a serious stroke and will be the recipient of some sympathy from voters in the Land of Lincoln. Democrats lack many serious recruits to challenge him outside of the Chicago area; a portion of the state dominated by a political culture that is increasingly held in low regard by downstate voters.

Johnson is perhaps a bit too conservative for his state’s electorate, but Wisconsin is fickle. The Badger State has been trending towards Republicans for several cycles, and Wisconsin has a rich history of electing figures of varying political extremes to high office. The state that sent both Robert La Follette and Joseph McCarthy to the U.S. Senate may not be uncomfortable being represented by the politically incompatible Johnson and liberal Democratic Sen. Tammy Baldwin.

Of all of the GOP’s vulnerable 2016 candidates, Toomey may be the most exposed. Pennsylvania is a blue state, particularly in presidential years. What’s more, the Pennsylvania Democratic Party has a strong farm team from which to draw Senate candidates. But state Attorney General Kathleen Kane, once Toomey’s most serious prospective challenger, has just suffered a spectacular implosion that will neutralize her as a threat to Pennsylvania Republicans and may tarnish the brand of the Keystone State’s Democratic Party.

“Court documents released Wednesday via a Supreme Court order show that the grand jury investigating alleged leaks recommended criminal charges against Attorney General Kathleen Kane,” PennLive.com reported on Wednesday.

“We find reasonable grounds to believe that various violations of the criminal laws have occurred,” one document, signed by the foreperson for the 35th statewide investigating grand jury, reads.

The grand jury recommended Kane be charged with perjury, false swearing, official oppression and obstruction, according to The Associated Press.

Another document, signed by William Carpenter, the supervising judge, states that the grand jury presentment is “supported by probable cause and establishes a Prima Facie case against Attorney General Kathleen Kane.” That document formally accepts the presentment.

Whether Kane faces prosecution for alleged wrongdoing is in the hands of the Montgomery County District Attorney, but the indictment is serious enough to scuttle her political career.

In November of 2013, Kane was considered Toomey’s biggest threat. A Public Policy Polling survey from that month found her leading Toomey by 4 points at 46 to 42 percent support. That survey also found Toomey running tied with his 2010 opponent, former Rep. Joe Sestak, at 42 percent. Flash forward to Tuesday and a new PPP poll testing the Senate landscape in Pennsylvania found Kane trailing Toomey by 6 points despite enjoying more name recognition among Keystone State voters. What’s more, in spite of uninspiring job approval numbers, Toomey leads in a hypothetical matchup against Sestak with 40 to 36 percent support.

“We tested 6 potential candidates against Toomey,” PPP revealed. “The only one who leads, and a very unlikely candidate, is former Governor Ed Rendell. He would start out ahead of Toomey 44/41. Rendell’s favorability is 43/42, which while not exactly setting the world on fire, suggests there’s been a lot of improvement in his image since he left office.”

Now, caveats abound. 40 percent support for an incumbent is nothing to celebrate – in fact, it signals just how terribly vulnerable Toomey will be in 2016. The Keystone State’s GOP is a wounded animal and, in 2014, Pennsylvania became the only state in the nation to oust a sitting Republican governor. Furthermore, the dynamics of the presidential race in 2016 will have a significant bearing on the electorate that ultimately turns out in November of that presidential year. To make any prediction in the race this far out is a fool’s errand.

All these provisos aside, it is nevertheless true that Kane’s spectacular collapse has jeopardized the Democratic project of retaking the Senate from the GOP.