Let's say we put an NCI check box on the 1040...
Imagine if on the tax forms, right after the "do you want $1 of your taxes to go to the election fund?" there was one that said, "Do you want $5.00 of your taxes to go the government funded National Cancer Institutes?"
Who would say no? (But either everyone's taxes would be slightly higher to offset the lost general revenue or it would end up tacked onto the deficit.)
Now then... how about if the check box was to ADD $5.00 to your tax total to be spect over and above the current budget allocation for NCI, and it would be treated on your taxes as the same as a $5 charitable contribution?
I see two sides here. It seems harmless to let people send in more tax that they can designate to something so worthwhile, but if it's so worthwhile then why not just fund it more in the first place, and there is a slippery-slope problem with the idea of voluntary taxation directed to pet projects.
So I could go either way.