Rep. Justin Amash is leaving the Republican Party saying, “Modern politics is trapped in a partisan death spiral, but there is an escape.” The Michigan congressman made the announcement in an op-ed he wrote Thursday for the Washington Post.

True to Washington’s fears, Americans have allowed government officials, under assertions of expediency and party unity, to ignore the most basic tenets of our constitutional order: separation of powers, federalism and the rule of law. The result has been the consolidation of political power and the near disintegration of representative democracy.

Amash, who was the only Republican to say Donald Trump should be impeached, goes on to say:

Preserving liberty means telling the Republican Party and the Democratic Party that we’ll no longer let them play their partisan game at our expense.

Today, I am declaring my independence and leaving the Republican Party. No matter your circumstance, I’m asking you to join me in rejecting the partisan loyalties and rhetoric that divide and dehumanize us. I’m asking you to believe that we can do better than this two-party system — and to work toward it. If we continue to take America for granted, we will lose it.