Whoever started the marketing campaign for breast cancer research is a genius. I see pink ribbons everywhere I go, on people, on cars, on buildings, even on telephone poles. Pink is now plastered on television sets everywhere as every NFL player, coach, and assistant is adorned with something of that hue.
I saw a few students selling baked goods to raise money for breast cancer research. I stopped to ask them if they thought the marginal dollar spent on breast cancer awareness and research could have been spent more effectively and efficiently elsewhere. It wasn't to scold them for raising money for a worthy cause, I was just interested in seeing how they would respond. I gave them a dollar donation.
A company has to allocate its scarce resources across many different venues. Should the next dollar be spent on advertising? Should it invest in more capital or new technology? Should it hire more labor? Would increasing the compensation of current workers lead to more production? Should it donate that dollar to some cause? The market mechanism disciplines firms to allocate those dollars most effectively and efficiently. If not, the firm loses profits and may even go out of business.
There is no market mechanism with donations to charitable organizations like breast cancer research, so it may seem inefficient. Maybe that last dollar spent on breast cancer research and awareness could have been better used elsewhere, such as on my favored cause, melanoma research.
But in a sense, this isn't much different than a market. The cause of breast cancer research was backed strongly enough that it mobilized women and men (mostly women) everywhere to voluntarily champion the cause in order to raise tons of money. Other causes, including melanoma research, have not been as successful in raising both awareness and money. This, however, is likely due to a) other causes not affecting as many people as breast cancer, and b) those who are affected by other causes have not been as passionate about their causes. Given that donations are voluntary, the money is likely going to where it is valued most and improving the lives of more people.
But here is where non-market exchange fails. When money is taken by force, including and especially through taxation (and public debt is just deferred taxation), the marginal dollar spent (actually, trillions of dollars) is largely wasted. There are many examples, but the "War On Drugs" is most noteworthy.
UPDATE: If you're a true Keynesian you would simply say that the blue line (addiction rate) would have been higher had the $1.5 trillion not been spent.