Protocol question: "Hillary Clinton made the list, but not her husband"

Factual Questions
1

The Prime Minister of India, Dr. Manmohan Singh, is being hosted by US President Barack Obama at the first state dinner of his administration.

From CNN:

Note: Emphasis mine.

I’m assuming the reasons were because of protocol issues and not personal issues. Is this a correct assumption? Would her husband have been invited if he was not a former president?

How would protocol change if President Clinton was also invited? How would it affect, say, dinner seating, among other things?

Does this mean Secretary Clinton cannot take her husband along to state events because of the protocol complications it may cause? Or is it because President Clinton might take the limelight away from Secretary Clinton?

2

There was a mayor in eastern Canada (St. John, New Brunswick, IIRC) who was quite a character. His most famous line was during the arrival of the Queen and her husband during an official tour many decades ago. He said during his speech:

“Prince Phillip, we are pleased to welcome you and your lovely wife to our fair city.”

Apparently the prince roared with laughter. The queen allegedly cracked a smile too.

Almost as funny as a few days later when the premier of New Brunswick at the time had his marijuana confiscated; even the premier does not escape having his luggage searched when he gets on a jet with the queen.

Protocl can be a funny thing.

3

I doubt there is any specific exclusion occuring. If the event is suitable for partners to attend, they attend. If the event is not suitable for partners, they don’t. Bill will be there either as a partner, or as an ex-president. Attending as an ex-president would be very rare. After all, GWB wasn’t invited.

4

I thought of that as a possibility, but it seems from the list of invitees that many others had their spouses invited:

5

Is it possible that Mr. Clinton’s status as an ex-president would require the two Bushes and Mr. Carter to also be invited if he attended? An example of “Protocol holds that if you invite one former president to a public event, you have to invite all of the living former presidents”?

6

Even if that were true, I’d think that would only count if President Clinton were invited AS a former President, and not as a +1.

7

Perhaps Clinton had himself un-invited, not wanting to upstage anyone . . . or sore that he’d be upstaged.

And I see Oprah was a no-show.

8

I thought it might have been a decision they (Mr. and Mrs. Clinton) made together. And by together, I mean, Hilary made a decision and Bill said “okay.” It may be prudent for her career to thoroughly establish herself on her own, instead of (at least some people say this) riding Bill’s coattails.

9

This might have been the case, but one of the things I’m curious about is whether “do not invite an ex-president” is part of the protocol.

If not, were he invited and had he accepted, what changes would have needed to be made at the event?