Shortly after President Obama started his second term, a loose-knit coalition of conservative activists led by former Attorney General Edwin Meese III gathered in the capital to plot strategy. Their push to repeal Mr. Obama’s health care law was going nowhere, and they desperately needed a new plan.

Out of that session, held one morning in a location the members insist on keeping secret, came a little-noticed “blueprint to defunding Obamacare,” signed by Mr. Meese and leaders of more than three dozen conservative groups.

It articulated a take-no-prisoners legislative strategy that had long percolated in conservative circles: that Republicans could derail the health care overhaul if conservative lawmakers were willing to push fellow Republicans — including their cautious leaders — into cutting off financing for the entire federal government.

“We felt very strongly at the start of this year that the House needed to use the power of the purse,” said one coalition member, Michael A. Needham, who runs Heritage Action for America, the political arm of the Heritage Foundation. “At least at Heritage Action, we felt very strongly from the start that this was a fight that we were going to pick.”

Last week the country witnessed the fallout from that strategy ........