• Portman joins Romney for debate prep in Vermont

    Brian Snyder / REUTERS

    Republican presidential candidate and former Massachusetts Governor Mitt Romney and U.S. Senator Rob Portman, R-Ohio, talk after a campaign rally in Cincinnati, Ohio September 1, 2012.

    By NBC's Andrew Rafferty and Garrett Haake

    WEST WINDSOR, VT -- Ohio Sen. Rob Portman came close to being Mitt Romney's most important defender, but, starting Tuesday, he is the Republican presidential nominee's biggest rival.

    Portman joined the Republican presidential nominee on Tuesday to help out with preparations for this fall's debates. Portman is playing the role of President Obama during these initial practice sessions located in the remote woods of Vermont. 

    "It's quiet and there are no distractions," said a senior Romney adviser of the 134-acre estate of former Massachusetts Lt. Gov. Kerry Healey. It's not in a swing state and far from any major TV markets.

    Portman was among the top contenders to be chosen as Romney's running mate.  But now, instead of spending his days campaigning throughout the country, he is holed up with top Romney advisers preparing for three of the most important evenings of the presidential race. Top Romney aides Beth Myers, Stuart Stevens, Lanhee Chen, Fehrnstrom, Ed Gillespie and Peter Flaherty have all descended upon the home, as well.

    It's a role Portman knows well, having played Obama during Sen. John McCain's practice presidential debates in 2008.

    The Romney campaign, backed by the RNC, is holding its own counter-convention in Charlotte this week, primarily challenging the president's record on the economy. Andrea Saul discusses.

    And while this may be familiar territory for Portman, it is relatively unexplored terrain for Romney.  Even after participating in 19 debates throughout last fall and the early part of 2012, Romney never prepared by engaging in mock debates.  Instead, advisers say, the former Massachusetts governor preferred to sit with advisers and float possible questions and answers. But, a one-on-one debate is different, and that is why Portman is in The Green Mountain State.