Romney fires back at Obama's negative ad

Mitt Romney's campaign responds to Barack Obama's newest negative commercial, released today, by putting out a spot focused on Steel Dynamics -- a company that experienced considerable growth after Romney's Bain Capital put money behind it.

This is literally a steel vs. steel war, as Obama's ad told the less happy story of GST Steel.

The Obama spot is running in Colorado, Iowa, Virginia, Ohio, and Pennsylvania. No word yet on whether the Romney ad will go beyond the web.