The Rehberg campaign said the travel came as part of the foreign operations appropriations subcommittee that funds and oversees embassies. It said the congressman also promoted Montana trade, but did not offer specific examples.
"If Sen. Tester really cared one bit about how taxpayer money is spent, he wouldn't have rubber-stamped President Obama's liberal agenda, under which we've seen billions upon billions of dollars in wasteful government spending that has failed to create the jobs he and Obama promised Montanans," said Rehberg spokesman Chris Bond.
The trips, known as CODELs, were established for congressional fact-finding, education and oversight of programs, according to Rob Walker, an election law and government ethics attorney in Washington D.C who used to staff House and Senate ethics committees. He said the rationale behind them is that it is best to have congressional members better informed by facts on the ground.
But there have been some perceived abuses over the years, which led to tighter rules in 2010, Walker said.
Tester argues they shouldn't be used to see tourist hot spots and to dine with federal contractors.
"The bottom line is, what did you really gain in knowledge that you couldn't gain by just talking to these lobbyists back here?" Tester said. "What did you get out of it?"