This video is excellent.
In it, former President Bill Clinton explains how Romney’s $5 trillion tax cut gives multimillionaires like him a new $250,000 tax cut, even with closing upper-end loopholes and deductions, and how it is mathematically impossible to pay for the $5 trillion tax cut without cutting deductions for the middle class, like the home mortgage, charitable, and state and local taxes deductions.
Romney won't give details on his tax plan because if he did, this is exactly what would be revealed to voters, and that's also why "the new Mitt Romney" denied that this tax cut even existed in his first debate with President Obama.
There's simply no way to give Romney's tax cuts to the wealthy without the middle class taking the hit. The math doesn't add up.
It's a simple explanation and worth taking the time to watch, and worth passing along.