By Andrea Shalal WASHINGTON (Reuters) -The White House on Thursday said Nippon Steel Corp’s $14.9 billion proposed acquisition of U.S. Steel Corp deserves “serious scrutiny,” given the company’s core role in U.S. steel production that is critical to national security. In its first substantive statement on the deal, the White House said it viewed a strong domestic steel industry as vital to the U.S. economy and national security and supported a careful review of the transaction by the Committee on Foreign Investment in the United States. National Economic Council Director Lael Brainard said Pre…