The Republican Party Dislikes Social Security, And Seeks To Privatize It
The Republican Party has supported Social Security since its inception, see Politfact.
In the 1950s, support ran as high as 8 or 9 to 1 in Congressional votes. President Dwight Eisenhower, a Republican, said : "Should any political party attempt to abolish social security, unemployment insurance, and eliminate labor laws and farm programs, you would not hear of that party again in our political history."
In 1983, President Reagan signed an increase in taxes in order to save Social Security from insolvency. That reform passed a GOP-controlled Senate by a margin of 4 to 1.
In 2005, President Bush proposed modifying the Social Security system to include private accounts. That plan did not get out of a GOP-controlled committee.