Do you mean by this: “All creationists accept design arguments, but not all who accept design arguments are creationists?” Then yes, that’s how I’ve always understood the distinction made by Discovery.
I was never a creationist in the common sense of the term (literal reading of Genesis, earth only 6,000 years old, etc.). In fact, in my youth I was a virulent anti-Creationist and textbook Darwinian. I used to go around looking for Creationists to fight with! I could have vied with Nick Matzke and some of the people here for the ability to project withering scorn. When I was still in high school, I already wrote as if I were the authority on what “science” says about origins. My Bible back then wasn’t the Bible, but the writings of people like Asimov and Sagan and Bertrand Russell. Evolution was my secular substitute for the Genesis story. (I’m actually quite embarrassed by some of the polemics I wrote against Christianity back then, not because I’m worried about my soul – I’m sure God forgives the immature excesses of youth – but because I used intellectually discreditable means to belittle my opponents, means which I still see being used widely in online debates.)
I’m a “creationist” now only in the broad sense that all Christians, Jews, and Muslims are creationists. But that sense would include Ken Miller and Francis Collins – two people whom Eugenie Scott and the NCSE never include in their relentless attacks on creationism.
As for intelligent design in nature, I had long before hearing about ID or TE/EC decided that nature showed evidence of design, but my arguments were either philosophical, or based on macroscopic scientific knowledge (Paleyan sorts of argument about the amazing mechanics of the bones, etc.). I did not know that anyone was working on more rigorous arguments at the biochemical level.
When I read Behe’s arguments for design, I didn’t agree with all of them, but I thought some of them were pretty strong. I’m still unconvinced by any of the “co-option” arguments for the accidental evolution of the flagellum, for example. Later I read Denton’s Nature’s Destiny, and at the time thought it was actually the best argument for ID in print, because it rested less on single isolated examples (flagellum, etc.) and more on the general conspiracy of features of nature to render the universe fit for intelligent life. Denton’s three more recent small books (all published by Discovery) continue in that vein.
Note that neither Behe nor Denton are “creationists” in the popular sense of the term. Behe is a Catholic who accepts common descent all the way up to the human body (which certainly is not accepted by Protestant creationists), and Denton is at best a Deist of some sort for whom the Bible has no bearing on the scientific discussion of origins. If the DI were a strictly “creationist” organization, it would not have published all those books by Denton, and would not promote Behe as heavily as it does. (In fact, ID has come under criticism from some creationists for not taking a firmer stance against common descent, but the DI has stuck to its guns, and maintains Denton and Behe on its Board of Fellows, and promotes their ideas.)
Thus, there are examples within the ID movement of people who do not oppose design to evolution, but embrace both. And that’s roughly where I place myself. I think of evolution, in the sense of “descent with modification,” as an account of earth history that is very plausible, and I take it as my working conception. (Though not as sacrosanct truth that only an ignoramus could contest – I resist all dogmatism on the matter.)
Actually, my “defense” of ID has not been “ID is true”, but more like “ID has been mischaracterized,” “ID has been unfairly treated,” and the like. I’m not trying to get anyone here to say, “Behe and Dembski’s arguments are valid, and ID is correct.” I’m merely trying to counter the sort of generic hostility that arises from certain members of the scientific community (and their groupies among the public) against any suggestion of design, teleology, etc. in nature. There’s no doubt in my mind, after years of reading and debating with anti-ID folks, that there is more than a scientific hostility to ID; often there is a visceral rejection of the idea of design, and that rejection comes from metaphysical and religious commitments.
I’d be happy if those who don’t accept design would at least admit that there are some features of nature which strongly suggest design and that ID folks aren’t betrayers of the spirit of science for wanting to talk about and investigate those features using the tools of science. Even Dawkins admits that living things appear designed. He understands that the appearance of design needs an explanation. In that sense, though he comes to conclusions diametrically opposed to those of Behe etc., he understands the issue of design better than some of his atheist colleagues. I still recommend Dawkins’s book The Blind Watchmaker as an excellent introduction to the classical neo-Darwinian view of evolution. Behe liked it for that purpose as well.