WASHINGTON — Congressional Republicans are moving to gut many of President Obama’s top priorities with the sharpest spending cuts in a generation and a new push to hold government financing hostage unless the president’s signature health care law is stripped of money this fall.

As Mr. Obama prepares to deliver a major economic address on Wednesday in Illinois, Republicans in Washington are delivering blow after blow to programs he will promote as vital to a more robust economic recovery and a firmer economic future — from spending on infrastructure and health care to beefing up regulatory agencies. While Mr. Obama would like to keep the economic conversation lofty, his adversaries in Congress are already fighting in the trenches.

On Tuesday, a House Appropriations subcommittee formally drafted legislation that would cut the Environmental Protection Agency’s budget by 34 percent and eliminate his newly announced greenhouse gas regulations. The bill cuts financing for the national endowments for the arts and the humanities in half and the Fish and Wildlife Service by 27 percent.

For the fiscal year that begins Oct. 1, Mr. Obama requested nearly $3 billion for renewable energy and energy efficiency programs — a mainstay of his economic agenda since he was first elected. The House approved $826 million. Senate Democrats want to give $380 million to ARPA-E, an advanced research program for energy. The House allocated $70 million.