Acongressperson is able to defend his or her votes to spend money on model preschool programs by pointing out that

I believe the answer is: saves money by reducing delinquency and use of the welfare program

Investment in a better  model preschool programs  would most likely resulted in higher quality of alumni in the future. This give the district with more skilled workers, improving average income, and reducing overall crimes since the economic pressure to do the crime is reduced.