Objectivism provides the essential philosophical basis for individualism and long-term rational selfishness required to properly support political conclusions in favor of freedom. Libertarians, on the other hand, don't know or understand the philosophy from which many of their political conclusions were copied, and are thus susceptible to reverting to political conclusions that appear momentarily practical, or consistent with altruism (which many libertarians implicitly embrace).
On top of that, "libertarian" has come to means so many things that it means nothing - there are libertarians in favor of and against abortion, in favor of and against anarchy, in favor of and against anti-trust regulation, to name a few random examples.
Objectivism isn't pervasive enough yet for political change based on it to occur, and libertarianism is a political dead end (because it's not consistent with the terrible mixed bag of present-day American values, or with itself.) So if you consider yourself a libertarian, and you don't like where Welch and his ilk are heading, I invite you to read Ayn Rand and new scholarly works that examine her philosophy deeply (Tara Smith's "Ayn Rand's Normative Ethics: The Virtuous Egoist".)