President Barack Obama has nominated energy executive John Bryson as the new US Commerce Secretary.
If confirmed by the Senate Mr Bryson will replace Gary Locke, whom President Obama has chosen to become the US ambassador to China.
Mr Bryson, 67, was chairman and chief executive of energy group Edison International from 1990 to 2008.
But Republicans warned that Senate confirmation of the appointment was not guaranteed.
There is strong Republican support for three proposed trade pacts with South Korea, Colombia and Panama, left over from the Bush administration, but many Democrats remain opposed despite changes negotiated by the White House.
A spokesman for Senate Republican leader Mitch McConnell sent an email to reporters noting that 44 Republican senators had signed a letter in March saying: "We will use all the tools at our disposal to force action [on trade agreements], including withholding support for any nominee for commerce secretary and any trade-related nominees."
But business groups supported the nomination and urged swift Senate approval.
President Obama described My Bryson as "a business leader who understands what it takes to innovate, create jobs and to persevere through tough times".