 The horrendous casualties and suffering endured by communist units during these sustained operations were beginning to tell . The fact that there were no apparent military gains made that could possibly justify all the blood and effort just exacerbated the situation . During the first half of 1969 , more than 20 @,@ 000 communist troops rallied to allied forces , a threefold increase over the 1968 figure . On 5 April 1969 , COSVN issued Directive 55 to all of its subordinate units : " Never again and under no circumstances are we going to risk our entire military force for just such an offensive . On the contrary , we should endeavor to preserve our military potential for future campaigns . " 
