A leading human rights advocate in Congress is calling on the Obama administration to enlist former President George W. Bush to help broker an end to the violence in South Sudan. 

Rep. Frank Wolf, R-Va., wrote to Secretary of State John Kerry on Monday urging the State Department to seek the help of the former president, citing his work in the region. 

"It's been said that politics stops at the water's edge," Wolf wrote. "While perhaps not always the case, I would hope that this administration, despite its past differences with Bush administration, would recognize the wisdom of inviting former President Bush and key members of his team who forged lasting relationships with the leadership of South Sudan to engage in high-level diplomacy with the various actors involved in the current crisis and to do so with the full support and blessing of the U.S. Department of State and the White House." 

It's not clear whether Bush, who largely has remained out of the spotlight since leaving office, would want to engage in such a role. But Wolf lauded the Bush administration's diplomatic work in Sudan -- engagement from that administration, and the Obama administration, helped lay the groundwork for the 2011 referendum which resulted in South Sudan becoming an independent nation. 

But the future of the world's newest country is now in question, with heavy fighting seizing pockets of South Sudan. The fighting started in mid-December, between the incumbent government and rebel forces loyal to former Vice President Riek Machar. 

The U.S. military has been positioning troops in nearby Djibouti amid the violence. A State Department spokeswoman said Monday that Kerry has been in regular talks with officials on both sides of the conflict, and the focus now is on bringing the parties to the table. 

Wolf argued in his letter that sending Bush would send a "clear message" that the people of South Sudan have not been abandoned. 

"Indeed we are at a crisis point and time is of the essence," he wrote.