Brock is calling the tactic nasty, negative campaigning, and says appearances by Virginia Gov. Bob McDonnell and Maine Gov. Paul LePage at his events in the coming weeks don't mean he agrees with them on every issue.
The Democratic Party issued a statement Tuesday criticizing LePage's stands on organized labor, health care and other issues.
McDonnell has drawn fire from Democrats for supporting a Virginia law requiring women to have an ultrasound before an abortion.
Brock says he thinks Vermont might be able to learn from Maine on health care. But he says government should not be involved in abortion.