In case you were wondering, yes, Virginia, politics in the United States are becoming more polarised. Olympia Snowe, the moderate Republican senator from Maine, is not running for re-election. And so the Senate is left without one more centrist counterweight to an extreme. To try and show how extreme, this graphic from the New York Times plots how often senators voted with their party.
While the chart does not have a marker for the average of each Congress, everyone can see the general trend line. Up. And up means less compromise. And less compromise means getting less done.