The so-called conservatives love the original intent of the constitution — unless that intent is contrary to the conservatives’ currently dominant political agenda of weakening the nation.
Take the following language from the 14th Amendment: “All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States.” This in fact is one of the few instances where there really can be no debate about what the drafters of the constitution meant: they meant at a bare minimum that any baby born in the United States was an American. Conservatives who worship at the sandals of Scalia and Thomas, however, say the founders could not have meant this language to automatically confer citizenships on the children of illegal immigrants, and so, they say, Congress has the authority to pass a law preventing such U.S.-born kids from being citizens.
Of course, they are wrong; in this particular instance, the language of the constitution is unambiguous, and thus Congress has no power to alter the born-in-America rule. If the anti-immigrant conservatives want to change this rule, a statute won’t do it; they'll need to amend the constitution.
(All this constitutional interpretation is quite aside from the political debate: I see citizenship for those born in the U.S. as one of the principal foundations of America’s rise to greatness, and abandoning that rule – whether through statute or constitutional amendment – would substantially weaken the country at home and abroad. And here’s something you might ask your neighborhood conservative: isn’t just now an odd time to be moving to the French system of denying full citizenship to those born in-country?)