We know that the White House now gives us a "tax receipt" showing how our tax dollars are being spent by the government. Taking this point further, how about the ability to choose how our tax dollars should be spent by the government?
We would like the ability to choose how five percent of our tax dollars are spent. Congress can continue to decide what to do with the other 95%.
By allowing citizens to get involved in government-spending decisions, we are exercising democracy. In this computer age, it is very easy for most citizens to log to a government webpage and make their desires known directly, without having to go through a representative.
Citizens might choose to put their five percent of taxes into defense, others into education or infrastructure... this is real democracy!