Donald Trump hit the number of delegates needed to grab the Republican Party nomination.
"Trump has gotten a polling bump from nailing down the GOP nomination," Brookings Institution Senior Fellow Darrell West told Xinhua. "Party leaders are endorsing him and he has made tremendous progress in unifying the Republican party".
"This is helping him greatly in the fall campaign against Hillary Clinton", said West. "As of right now, he has a more unified party than Clinton does".
Trump unveiled an "America first" energy plan for production of oil, coal, natural gas and other energy sources.
The GOP candidate said that he want to push the United States toward energy independence.
"Clinton declared war on the American worker," Trump said of Lady Hillary.