President Trump is betting that, by touting deregulation and deriding his Democratic opponent as an extremist who will raise taxes and throw wrenches into oil and gas development, he will galvanize domestic energy industry support ahead of the November election.

Culminating the Republican National Committee (RNC) convention Thursday night in Washington, DC, Trump claimed his administration had “secured for the first time American energy independence” with “record-setting tax and regulation cuts at a rate nobody had ever seen before.”

Democratic Party nominee Joseph R. Biden Jr., meanwhile, would hike taxes, abolish the production of oil, natural gas and coal, and “lay waste” to the energy sector while crippling the U.S. economy, Trump said without citing...