Charitable Tax Exemption?

[Vagos]

This article outlines many Libertarian ideas on how to deal with poverty here in America. Read the whole article if you wish, but the part I chose to draw attention to for this topic was the last section at the bottom titled "Charitable Exemption?". In it the author, Arnold Kling, outlines a plan to basically allow people a charitable tax exemption up to $20,000. Meaning that if your taxes are 20k or below, you can choose to instead donate that amount of money straight to a charity of your choosing and not have to pay the amount in taxes.

The logic behind this is that charities have to answer more to their contributors than the government has to answer to its taxpayers. Charities can do a better job of directly affecting people who are in need of help, rather than the government just taking money from some people and sending it to others. Read the article and discuss.

What would be the pros and cons of this situation?
Would it backfire or would it prove to be a more effective way of dealing with poverty?