Why should it not be? It is the procedure spelled out in the Constitution for confirming judges to the Supreme Court. If he fails to uphold the Constitution as is his duty, impeach him.
"If he fails to uphold the Constitution as is his duty, impeach him." - thoughtomator
Nice, were it politically doable - which it is not. If you really want originalist judges, you had best select them through the confirmation process.
Of course, if you only want to genuflect before President Bush, then you should by all means support Roberts' confirmation with utterly no examination of his judicial philosophy.