First, I am a rationalist, or free thinker, which eclipses both liberal and conservative philosophies. And by that, I mean that I view the evidence in assessing the data, NOT an indoctrinated conclusion assessed by others, and in this case BOTH religion and materialist oriented science regarding evolutionary theory.
That said, I'll now give you my interpretation of ID within biology. It is simply an adjunct hypothesis regarding causative factors in producing functional complexity, and sits with equal status along with natural causation. Both are valid hypotheses, and IMO, both were operatives in the evolutionary processes.
So in answer to the question, first, we need definitions.
Evolution = an overall set of processes which have culminated in living organisms.
Intelligent Design = not a separate theory from ToE, but a causative hypothesis entailing directed input at key points, by a single or multiple intelligences, and NOT based on scriptural accounts.
Natural Selection of genetic variation = a causative hypothesis entailing non-directed input to phenotypic advancements, which result in fecundity advantages based on sexual and environmental selective pressures.
Horizontal Gene Transfer and other natural processes are hypothesized to produce upward complexity and novelty as well. All of the above are hypothetical and equally viable at this time.
Now that ID is properly understood and defined, it sits within evolutionary theory in addition to natural causative factors, and cannot be ruled out summarily. It is thus a legitimate concept for discussion and further research, classrooms included.