WASHINGTON  House Democrats were preparing late last year for the first floor vote on the financial regulatory overhaul when Representative John A. Boehner of Ohio and other Republican leaders summoned more than 100 industry lobbyists and conservative political activists to Capitol Hill for a private strategy session.

The bill’s passage in the House already seemed inevitable. But Mr. Boehner and his deputies told the Wall Street lobbyists and trade association leaders that by teaming up, they could still perhaps block its final passage or at least water it down.

“We need you to get out there and speak up against this,” Mr. Boehner said that December afternoon, according to three people familiar with his remarks, while also warning against cutting side deals with Democrats.

That sort of alliance  they won a few skirmishes, though they lost the war on the regulatory bill  is business as usual for Mr. Boehner, the House minority leader and would-be speaker if Republicans win the House in November. He maintains especially tight ties with a circle of lobbyists and former aides representing some of the nation’s biggest businesses, including Goldman Sachs, Google, Citigroup, R. J. Reynolds, MillerCoors and UPS.