Republican Sens. Ted Cruz and Mike Lee are urging President Trump not to appoint as ambassador to Colombia a prominent career State Department official who served as a top aide to former Secretary of State Hillary Clinton and worked closely with her in the aftermath of the Benghazi attacks.

Joseph MacManus, a 30-year veteran of the foreign service, is a top candidate to become ambassador to Colombia and was considered the frontrunner before conservatives began voicing opposition to his nomination a few weeks ago, according to several GOP sources.

His nomination has the support of both Secretary of State Rex Tillerson and Tom Shannon, a career foreign service diplomat who serves in the State Department as undersecretary for political affairs and is considered Tillerson's right-hand man.

The two conservative senators this week expressed deep concern that MacManus was too close to Clinton during her tenure, doesn't share Trump's "America First" agenda and other conservative foreign-policy goals, and, as one of Clinton's closest advisers, was deeply involved in the State Department's initial response to the Benghazi attack.

Conservatives in Congress and the foreign-policy community argue that the role of ambassador to Colombia, Washington's staunchest ally in Latin America, is a critical one and any candidate for the post should have extensive experience in the region.

Click for more from The Washington Free Beacon.