On April 23, the Colorado Supreme Court unanimously removed Congressman Doug Lamborn from the Republican primary ballot. He has been in Congress since the 2006 election and he intends to run for re-election. He was removed because two of his petition circulators were not residents of Colorado when they worked on his petition. The petition requires 1,000 signatures of registered Republicans.
The case is Kuhn v Williams, 2018 CO 30. The decision is 28 pages.
In 2008, the Tenth Circuit ruled in an Oklahoma case that bans on out-of-state circulators are unconstitutional. Yes on Term Limits v Savage, 550 F.3d 1024 (2008). Colorado is in the Tenth Circuit. The Colorado Supreme Court did not mention the Yes on Term Limits decision, and said it is not expressing any opinion on whether the Colorado residency requirement for circulators is constitutional or not.
Presumably Congressman Lamborn will now bring a constitutional challenge. The Colorado primaries are on June 26, so any such constitutional case will need to move very fast. There are other Republicans on the primary ballot for the 5th district. Thanks to PoliticalWire for the news.