Can I say “the Iowa caucus result may ‘tip Newt Gingrich off’ GOP presidential ticket”?

Further to my question about the meaning of “Work on your issue” in Time magazine’s article, “Playing favorites,” there was another phrase I’m unfamiliar with in the subsequent sentence;

“One 2007 Norwegian study showed that firstborn have a 3-point IQ advantage over later siblings, partly a result of being the exclusive focus of their parents’ attention in the earliest part of life. These benefits accrue like compounding interest. A small IQ advantage may yield a similar edge in SAT scores, which may tip firstborn off the Harvard waiting list and into the entering class.

I looked for the definition and usage of the phrase, “tip somebody off someplace (Harvard waiting list / position, situation, whatever) in English dictionaries at hand, but was unable to find any relevant answer. They show “tip A off (off A)” as an idiom meaning “secretly inform a person / police about (against) something,” which I don’t think applicable to the above sentence.

From the context of the above sentence, I guess “tip somebody off someplace” means to place somebody successfully (or luckily) to someplace or status, but I’m not sure. What does “A similar edge in SAT scores may tip firstborn off the Harvard (entitlement),” exactly mean?

Can I apply the phrase to other instance, e.g. “The Iowa caucus result may tip Newt Gingrich off GOP presidential ticket”?

The usage of "tip X off Y" relates to a "tipping point", which in turn relates to "tipping over", so, in turn:

• Tipping over is falling from a (static?) upright position to another less-upright position. More often applied to containers than other objects I believe
• The tipping point is the angle at which any further motion/angle in a certain direction will ensure that the object falls
• To tip in some direction or into some location is providing that small additional push that makes the difference, causing the thing to fall to its new location

This is, as you noted, a completely different usage from "to tip X off [regarding Y]".

You could use it with respect to the presidential ticket, but there would need to be an article: “the Iowa caucus result may tip Newt Gingrich off the GOP presidential ticket”

By using the expression "tip X off of Y" the writer is implying a situation where there is a delicate balance which can be easily disturbed or that the situation being described is on the verge of changing and only a small action is required to cause the change to occur.

This is not a common idiom in English but is something that the writer has coined by referring obliquely to "tipping point", which is a common enough idiom.