Here's a new name you can add to the list of possible John McCain running mates, a Republican source tells me: Rep. Paul Ryan of Wisconsin, a member of the Ways and Means Committee. Although he's only 38, Ryan was elected to Congress back in 1998. So he has more national political experience than Barack Obama. What's more, he's a rock-solid, supply-side conservative who recently coauthored a bill that would create a simplified tax system. Under the plan, there would be two rates, 10 and 25 percent, a huge standard deduction of $25,000 for married filers (half that for singles), and a $3,500 personal exemption. It would eliminate all other deductions and credits that litter the current tax code. The dividend and capital-gains-tax rates would be made permanent at the current 15 percent. Other Ryan pluses: 1) he's from a swing state; 2) he's a family guy (three kids) who could help McCain appeal to suburbanites wanting to hear about more than just the war on terrorism; 3) he's a sharp-looking fellow.