Political polarization is one of the most dangerous problems facing the United States today.

Politicians are no longer celebrated for their ability to compromise; instead, they are criticized for being weak or disloyal when they try to find middle ground or (God forbid) change their stance on an issue after learning new information.

As a result, the majority of votes in Congress go along party lines, with nearly all the Democrats voting one way and nearly all the Republicans voting the other way. To go against your party in votes like this has become one of the cardinal sins of modern-day politics.

In a recently published study, a team of researchers used politician’s voting records to create a stunning visualization of the rise of political polarization in Congress – check it out.

To create the visualization, the researchers made a serious of network diagrams for every House of Representatives from 1949 to 2011. The Washington Post’s Christopher Ingraham explains,

“They’ve drawn dots for each representative, and lines connecting pairs of representatives who vote together a given number of times. Finally, the dots for each representative are placed according to how frequently the Representatives vote together overall.”

The pattern that emerges is impossible to miss — for the past 25 years or so, the House has been slowly tearing itself apart along party lines. Ingraham describes it as, “political mitosis… like a single cell dividing into two.”

Ingraham also notes that the dot clusters for both parties are becoming more and more tightly packed, showing that Representatives within each party are voting more similarly than ever before.

This dogmatic partisanship is crippling the U.S. legislature — Congress’s public approval rating shows that better than anything. Today, only 15% of Americans approve of the job Congress is doing. That number hasn’t been above 25% since Dec. 2009, and has been below 40% for more than 10 years now.

The last time that 50% of the country thought Congress was doing its job well? June of 2003.

Read more from the Washington Post. You can also check out Congress’s historical approval ratings from Gallup.