He emphasised that greater engagement with Myanmar would not mean the removal of sanctions against it, but his comments indicate that the US state department is considering a change of policy.
Campbell is the choice of Barack Obama, the US president, to become the next assistant secretary of state for East Asia, but he has not yet been confirmed in the post.
House arrest trial
Aung Sang Suu Kyi, a Nobel laureate and leader of the National League for Democracy (NLD), is facing trial for allegedly violating the terms of her house arrest over the visit of an American man, John Yettaw, to her house.
The 63-year-old opposition leader's legal team and members of her party say Yettaw's visit was uninvited and she only agreed to let him stay after he pleaded with her that he was unwell.
Yettaw allegedly swam to her lakeside home on two occasions, sneaking past tight security that surrounds the compound.
He was arrested in May after trying to swim back across the lake from his second visit.
Yettaw and two women members of the NLD who live with Aung San Suu Kyi are being tried with her on the same charge.
Aung San Suu Kyi has been detained in jail or under house arrest for more than 13 of the past 19 years.
The trial has drawn outrage from the international community and her supporters, who say the military government is using the case as an excuse to keep her detained during elections scheduled to take place in 2010.
The NLD won Myanmar's last elections in 1990 but was not allowed to take power by the military, which ignored the result.
Critics of the government say the vote next year is a sham designed to cement the military's continued hold on power.