You were extremely gracious last year to make the case for everyone in your cast to enter the supporting categories. And based on screen-time, your argument is valid. However, you or one of your co-stars will always be snubbed by Emmy voters if you stay in the supporting category.
Your show has never been hotter in the ratings and is the reigning Emmy champ as Best Comedy Series. That means that Emmy voters will want to give "Modern Family" even more Emmy nominations next time.
Emmy voters have never nominated four Supporting Actors from one comedy at one time. Even if you are able to get a supporting nomination next summer, it almost certainly means that one of your co-stars will be snubbed.
You have been working on television for over 25 years and are well-liked within the industry. People would really love to give you a nomination if given a reasonable chance.
If you are the only "Modern Family" man entered in the Best Actor category, you will be guaranteed a nomination. Alec Baldwin, Steve Carell and Jim Parsons will certainly return to the race, but Emmy voters will be faced with an open slot now that Tony Shalhoub is gone. Matthew Morrison may also return, but beyond these names there really aren't many legitimate contenders for this category.
While you do have the same amount of screen-time and storylines as your other adult co-stars, the show revolves around the fact that you are the father, grandfather or father-in-law of every character (except for Sofia Vergara). That gives your character the weight to be considered lead even though the others are supporting. (Sidenote to Vergara — This does not mean that you should move into a category that has way, way too many ladies for the six available slots).
Photo: Ed O'Neill in "Modern Family" (ABC)