By the time President Donald Trump's first nominee for labor secretary withdrew from consideration, there was little doubt where he stood on the big issues facing the department.

In contrast, his replacement, Alexander Acosta, heads into his hearing Wednesday with far more experience in government, but comparatively opaque views on key matters he'll face at the Labor Department — including choices that could reshape conditions for millions of U.S. workers and stoke conflicts within Trump's base.

Now the dean of Florida International University's law school, Acosta served under George W. Bush as a member of the National Labor Relations Board before moving to the Justice Department. During his eight months at the labor board, Acosta sided frequently with management, including in a controversial 2003 decision that found it was legal for a clinic to fire nurses because they started a strike four hours later than they had said they would. But he hasn't weighed in publicly on recent policy moves, such as overtime expansion, which Trump's withdrawn nominee, CKE Restaurants Inc. CEO Andrew Puzder, inveighed against in op-eds and on television.