Cuccinelli appointed interim chief of Citizenship and Immigration Services

Former Virginia Attorney General Ken Cuccinelli (right) began Monday to take up his new position as Acting Director of the US Immigration and Citizenship Services (USCIS), a controversial appointment that could create a confrontation between the Republicans of the White House and the Senate.

President TrumpThe Donald John TrumpHouse panel seeks to block Pentagon funds for the border wall Giuliani evokes Joseph McCarthy in his reviews of Pelosi Giuliani evokes Joseph McCarthy in his reviews of Pelosi PLUS asked Cuccinelli to lead the agency, which manages the country's legal immigration system, at a time when it was trying to combat illegal migration and prevent immigrants from gaining benefits.

"Our country has the most generous legal immigration system in the world and we must zealously preserve its promises for those who come here legally," said Cuccinelli in a statement distributed by the Department of Homeland Security (DHS) . "I look forward to working with the men and women of the USCIS to ensure that our legal immigration system operates effectively and efficiently while deterring fraud and protecting the American people."

Cuccinelli's appointment took a few weeks to complete, while Trump was looking for another major immigration player at DHS.

He will replace Lee Francis Cissna, who was forced to leave his USCIS chief position late last month while the department had been revitalized by a major White House political advisor. Stephen MillerStephen MillerTrump Trade Advisor: Mexican fares do not have to come into effect "Trump Trade Advisor: Mexican Fares" May Not Have to Come Into Force "Trump's Mexican Fares Exhibit Administrative Divisions MORE.

Cuccinelli, however, could be faced with a path fraught if Trump pointed him out to direct the USCIS permanently.

Senate Majority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellTrump praises Mexico's agreement on migrants: will be "very successful" Trump praises Mexico's agreement on migrants: will be "very successful" Ambitious projects starting in 2020 are proposed with multi-billion dollar price tags MORE (R-Ky.) Long opposed to Virginia's former Attorney General, who dates back to the efforts of the Conservative Senate led by Cuccinelli to oust the Senate Republican in 2014. McConnell rose against Cuccinelli in April , while his enemy in the race to lead DHS.

"He has spent a good part of his career attacking Republicans in the Senate, which seems to me a strange position for him to seek confirmation from the Senate," Sen said. John CornynJohn CornynTrump: Senators "have no idea what they are talking about" when it comes to Trump rates: Senators "have no idea what they are talking about" when pricing Anxious GOP seeks to delay Trump rates in Mexico MORE (R-Texas) said last week, according to Politico. "It is unlikely that it will be confirmed when it is named."

Others expressed concern that Mr. Cuccinelli's appointment may reflect the Trump administration's intention to transform USCIS into an organization that distributes immigration benefits, such as visas and green cards, in an organization focused on the respect of the rules.

The head of a union representing USCIS employees said late last month that the selection of Cuccinelli would mean "the end of legal immigration as it currently exists".

"It has become clear that the purpose of this administration is to put an end to immigration all together. How to do it better then by designating as a USCIS officer, someone who knows nothing about immigration, status adjustment or naturalization and whose sole purpose is to destroy the agency that provides these benefits, "said Danielle Spooner, president of the American Federation of Trade Unions. Government employees, told CNN.

Updated at 12:07