Same reason Romney won't release them. Obama has released all his tax returns what is Romney trying to hide?
Republicans know that the 13 percent tax rate Romney paid in his only released return is only the tip of the iceberg. Romney will have some 0-5% effective rates mixed in there
How can Republicans sell their "Tax cuts for all....Regardless of debt" when their own standard-bearer is only paying 5% of what he earns?
I guess dwelling on Mitt's dog, his wife's horse and his tax returns that he isn't obligated to disclose beats addressing Obama's $5,000,000,000,000 debt in 3 years, record unemployment, dwindling US $, first credit downgrade, housing markets in the shitter, miserably low GDP, net loss of jobs, record numbers of Americans on public assistance, etc.