Once again, you avoid the simple fact that McVain wouldn't have even been on the short list if his politics hadn't been in line with the Supremely Nuanced Liberal, John Kerry.
Sorry you're having such a hard time dealing with that simple reality. Learn to cope.
Let's try this one more time.
For much of its existence, the office of Vice President was seen as a little more than a minor position.
John Adams, the first Vice President, described it as "the most insignificant office that ever the invention of man contrived or his imagination conceived."
Even 150 years later, 32nd Vice President John Nance Garner famously described the office as "not worth a pitcher of warm piss" (at the time reported with the bowdlerization "spit").
Thomas R. Marshall, the 28th Vice President, lamented: "Once there were two brothers. One went away to sea; the other was elected Vice President of the United States. And nothing was heard of either of them again."
When the Whig Party was looking for a vice president on Zachary Taylor's ticket, they approached Daniel Webster who said of the offer "I do not intend to be buried until I am dead."
The natural stepping stone to the Presidency was long considered to be the office of Secretary of State. It has only been fairly recently that this notion has reversed; indeed, the notion was still very much alive when Harry Truman became the Vice President for Franklin Roosevelt.
imo, staytrue prefers liberals. His FR resume defending them makes that quite evident.