Postgres Nested IF

this is strange, I was writing a function:

  IF CURRENT_DATE - v_recom_record.date_appended::date > 28 THEN
     IF v_recom_record.current_recommendation = 1 AND
        v_recom_record.zacks_rank = 3 THEN
        v_rec_rank := 3;
.
.
.
    EXCEPTION
    WHEN OTHERS THEN
.
.

And when I try and compile id:

zrecdev-# \i daily_recommendation_update.sql
psql:daily_recommendation_update.sql:126: ERROR:  syntax error at or near     "EXCEPTION"
LINE 61:          EXCEPTION

However, if I add a BEGIN between the IF statements:

  IF CURRENT_DATE - v_recom_record.date_appended::date > 28 THEN
     BEGIN
       IF v_recom_record.current_recommendation = 1 AND
          v_recom_record.zacks_rank = 3 THEN
          v_rec_rank := 3;

Compiles fine.

Does Postgres not allow 2 conditionals like that?