Being Constitutional

Why does it appear that some only think that we should abide by portions of the Constitution? The government is ratified to "...provide for the common Defence and general Welfare of the United States; To regulate Commerce...To promote the Progress of Science and useful Arts..." But some only want to "provide ...for the common Defence." Yet, some claim that the laws passed by others are unconstitutional. If the Constitution ratifies the provision for the "general Welfare" why do some say that this is unconstitutional? If the Constitution ratifies the "progress of Science" how can a president essentially decree through an executive order the restriction of science to study stem cells for life-sustaining illnesses? (I guess that's the prerogative of the president, eh?) And, pray tell why do we cut "useful arts" in schools and give so little to arts organizations? What about the banks? Why deregulate banks when commerce, according to the Constitution, should be regulated? (I guess it has to do with getting the balance right, eh? But the balance seemed to be working jut fine prior the the massive deregulation that began with President Reagan.) All of these, not just the provision of the "common Defence," are constitutional. I suppose some might think that it's not what we do but how we do it. Okay, but why haven't we been effective in governing? Yes, waste and abuse. But has our defense budget, with multiple billion dollar contracts to private corporations, lessen our ability to govern effectively? While we expect defense to have the lion's share in the protection of our country, we should be wiser in the reasons and ways that we launch our defense. To do otherwise would seem unconstitutional, for we will only be largely abiding by portions of the Constitution and not by others. I guess the argument might be that there are provisions for the "general Welfare," and the "progress of Science." But I would argue that if these provisions are unduly restricted and are so small that they can be drowned in a bathtub, as was suggested by the Republican Grover Norquist, are these indeed provisions?