There are a lot more similarities between "both sides" than that. They make a big show out of arguing over a small number of things they disagree on. But for many important things, they don't significantly differ.
The two parties do not significantly differ on indefinite detention of American citizens on US soil.
The two parties do not significantly differ on domestic spying, dragnet-style data collection and warrantless wiretapping.
The two parties do not significantly differ on allowing extra-judicial targeted killings.
The two parties do not significantly differ on the use of unmanned drones, either for combat or domestic surveillance.
The two parties both support pre-emptive "cyber" war and non-defensive hacking.
The two parties do not significantly differ on their support for continuing the War On Terror.
The two parties both support maintaining US military bases around the world.
The two parties do not significantly differ on favoring Keynesian economics.
The two parties support delegating monetary policy decisions to the Federal Reserve, including support for quantitative easing.
The two parties do not significantly differ on their use of earmarks and pork barrel spending.
Neither of the two parties have (recently) proposed plans for balancing the budget.
Neither of the two parties plans to significantly cut defense spending.
The two parties both favor taxpayer-funded foreign aid.
The two parties are largely backed by the same corporate sponsors and special interest groups, with a few key differences.
The two parties both backed TARP and in general favor bailing out companies too big to fail.
The two parties do not significantly differ on their general support of "economic stimulus" as a tool to prop up the economy.
The two parties do not significantly differ on their support for and allegiance to Israel.
The two parties both favor and continue sanctions on Iran.
The two parties do not significantly differ on their use of super PAC funding and their support of unlimited spending from corporations and special interest groups.
The two parties do not significantly differ on their use of gerrymandering to gain political advantage.
The two parties oppose any measures that would strengthen the viability of a third party.