Efforts by South Korean police to charge a nationalist over a knife attack on the U.S. ambassador have renewed debate about the use of a state security act as a political weapon and an attempt to gloss over security shortcomings.

Kim Ki-jong, 55, could face charges including attempted murder over the March 5 attack as well as violating the National Security Act, a 67-year-old statute that critics say has long outlived its purpose.

Many contend it is used by conservative governments to gag liberal political opponents by painting them as supporters of North Korea, with whom South Korea technically remains at war.