It's not hard to figure out why Congress can't get anything done. It boils down to simple numbers. Nothing can pass the House unless it is supported by the Republican majority, or unless the House Republican leadership is willing to put up a bill with bi-partisan support for a vote. And the Senate Republican minority will not allow most legislation to be put to a vote without 60 votes for cloture.
Is the message that American voters just don't understand the way their own government functions (or fails to function)? Or that they don't have the sense to do what is necessary to fix it, which most people in most other democracies in the world would tell you just means allowing one party or the other to assume control?
Or are Americans just manifesting the triumph of hope over experience? Gallup interprets the poll results to suggest that many people prefer divided government because they want Congress to compromise and enact a moderate agenda, fearing that complete control by one party or the other will produce legislation that is too extreme in either direction. Despite repeated demonstrations that many members of Congress consider it a betrayal of their principles to support anything that the other party might agree to, voters still continue to return those members to office, the most partisan voters demanding that their representatives never bend, while others expect them to compromise. We thereby place our own representatives in an impossible position, and then we blame Congress for a situation that we have created, and that we seem likely to perpetuate this coming November. (Remember Einstein's definition of insanity, which is to keep doing the same thing over and over again expecting different results.) But you could also argue that it's about time for Congress to get the message that they need to try harder to reach consensus more often, even though by doing that many members will have to risk their own seats.