abc was third with 12.3 , according to figures released tuesday by the a.c. nielsen co. ; as the jan. 15 deadline loomed for iraq to withdraw from kuwait or face military attack , greater numbers of viewers tuned in last week to nightly network newscasts. ; abc and peter jennings were no. 1 with a 12.5 average , followed by nbc and cbs with 11.5 each .