WASHINGTON — An informal coalition of influential conservative leaders and groups, some with close connections to the White House, has been quietly working to nurture protests and apply political and legal pressure to overturn state and local orders intended to stop the spread of the coronavirus.

The groups have tapped their networks to drive up turnout at recent rallies in state capitals, dispatched their lawyers to file lawsuits, and paid for polling and research to undercut the arguments behind restrictions that have closed businesses and limited the movement of most Americans.

Among those fighting the orders are FreedomWorks and Tea Party Patriots, which played pivotal roles in the beginning of Tea Party protests starting more than a decade ago. Also involved are a law firm led partly by former Trump White House officials, a network of state-based conservative policy groups, and an ad hoc coalition of conservative leaders known as Save Our Country that has advised the White House on strategies for a tiered reopening of the economy.

The effort picked up some influential support on Tuesday, when Attorney General William P. Barr expressed concerns about state-level restrictions potentially infringing on constitutional rights, and suggested that, if that occurred, the Justice Department might weigh in, including by supporting legal challenges by others. Separately, in Wisconsin, Republicans in the state legislature sued to block the Democratic governor’s order extending stay-at-home rules through May 26.