(New York Times) One of the country’s most influential conservative political organizations announced Wednesday that it was diving into a bitter Republican primary in Michigan, its first such intervention into the broader battle between the party establishment and Tea Party conservatives.

The group, Americans for Prosperity, will spend about $230,000 on advertisements thanking Rep. Justin Amash for fighting against President Obama’s signature health care law, officials there said — a shot at establishment donors who are rallying behind his challenger, Brian Ellis.

The ads do not attack Mr. Ellis, but the decision to get into a hotly contested primary on behalf of one of Congress’s most outspoken lawmakers hints at the delicate line the group is trying to walk. It is supporting conservatives seeking to reshape the party without committing itself to an expensive internecine struggle in the Senate that could endanger the party’s prospects for regaining control of the chamber this year.

Note: Read our discussion guidelines before commenting.