Fresh off his campaign bus tour, President Obama today signed into law an extension of low federal student loan rates and a transportation spending package that he championed around the country as a way to boost the economy.

"This bill will keep thousands of construction workers on the job rebuilding our nation's infrastructure," Obama said. "Second, this bill will keep interest rates on federal student loans from doubling this year, which would have hit nearly 7 1/2 million students with an average of $1,000 more on their loan payments."

The president cast the legislation as a welcome footnote to his campaign swing through Ohio and Pennsylvania, where he stressed his vision for boosting the middle class on a day that the Labor Department reported weak job growth for June.

"I believe with every fiber of my being that a strong economy comes not from the top down, but from a strong middle class," he said.

Obama added that the legislation would give the middle class a boost.

"For months, I've been calling on Congress to take half the money we're no longer spending on war and use it to do some nation building here at home," he said. "There's work to be done building roads and bridges and wireless networks. There are hundreds of thousands of construction workers that are ready to do it."

He added, "In today's economy, a higher education is the surest path to finding a good job and earning a good salary and making it into the middle class."

Obama called the legislation an "outstanding piece of business" and said that he's "very pleased that Congress got this done."

The president spent less than one hour at the White House before hitting the road again, this time to Camp David to spend the weekend with his family.