ONTARIO, OH -- Ohio Sen. Rob Portman on Tuesday called recent attacks against him by President Obama's campaign "desperate" and further proof they do not have a record to run on.

Speaking to reporters after touring a farm in Shelby, OH, Portman responded to emails from the Obama camp slamming him and other potential Republican vice presidential picks. 

"Rob Portman has been our senator for two years now, but the most damning pieces of his record involve choices he made as a senior member of the Bush-Cheney administration and conservative congressman, the consequences of which still reverberate on a national scale," said an email sent to Ohioans from the Obama For America state director. "As one of the architects of the top-down Bush budget, Portman practically invented the policies that punished middle-class families while exploding the deficit, and crashing our economy."

"I think the Democrats are getting kind of desperate," Portman said in response. "They don't want to talk about their record, and gosh, you can't blame them."

His connection to the George W. Bush administration has been one of the most talked about drawbacks of adding Portman to a national ticket. The former Office of Management and Budget chief is quick to defend his record, today saying "I'm proud of my service in the Bush administration." 

The junior senator from Ohio has kept a busy schedule since Congress began its August recess.  He's done a a mix of events in his home state -- both in his capacity as a senator and as a Romney surrogate.  But regardless of whether he's out on his own behalf or that of the presumptive nominee, nearly all his appearances these days feature Portman going on the offensive against the current administration and defending Romney.

And as speculation has grown about his chances of being named VP nominee, Portman has found himself spending more and more time defending his own record.  He points to his work for a balanced budget and deficit only a fraction what it is today as his ready answer to questions about his connection to Bush.

After touring the farm, Portman headed over to Ontario, OH to help open a Romney Victory Office there.  Though he said he plans to attend the Republican Convention in Tampa later this month, he said he has not had any communication about a speaking slot.

He did say, however, he is looking forward to some social events thrown by another member of the Ohio delegation, Speaker John Boehner (R-OH).

"The Boehner parties are always the best parties," said Portman. "I mean, come on, let's face it."