Looking at the results of Tuesday’s primary and special elections, Sen. Olympia Snowe had this observation:

“This is an election where people are sending a message from the ballot box,” she told the Huffington Post. “I think the message should be heard here (in Washington).”

Snowe is probably right, but what is the message?

Are voters fed up with Democrats? Tell that to Pennsylvania businessman Tim Burns, who lost the special election to fill the late John Murtha’s House seat to a Democratic opponent in a district that went to John McCain in 2008.

Are they mad at liberals? Ask centrist Democrat Sen. Blanche Lincoln, who will be forced to defend her seat in a runoff election against liberal Arkansas Lt. Gov. Bill Halter.

Are they anti-establishment? Probably. Candidates from both parties lost despite having support from the top echelons of their parties.

Anti-incumbent? Definitely. For the first time in three decades, incumbent senators from both major parties have been denied the nomination to run in November. While it’s hard to string a consistent narrative between these few results in a handful of states that may or may not be bellwethers for what to expect in November, there is a constant theme of cranky voters. We may not be able to predict what that’s going to mean next fall, but it’s clear that there are some themes candidates should heed.

Like the elections in 2006 and 2008, this election is shaping up to be all about change, and while Democrats benefited from that dynamic in the past two elections, they have the most to lose this time.

Reps. Chellie Pingree and Mike Michaud and whoever comes out of Maine’s Democratic primary for governor will have explain how having them in office is a vote for change. They may also have to overcome the loss of some moderate independents, who are turned off by a Democratic majority in Washington that some think has tried to do too much. They may also have to deal with a lack of enthusiasm from party activists.

But this doesn’t look like a year when a Republican can reliably draw on traditional wells of support either. Tuesday’s voters were hard on all insiders. Maybe the message is that voter anger is a powerful force, but one that is hard to contain.