During the Canadian rebellions, Charles Duncombe and Robert Nelson helped foment a largely American militia, the Hunters' Lodge/Frères chasseurs. This militia carried out several attacks in Upper Canada between December 1837 and December 1838, collectively known as the Patriot War. The administration followed through on its enforcement of the Neutrality Act, encouraged the prosecution of filibusters, and actively deterred U.S. citizens from subversive activities abroad. In the long term, Van Buren's opposition to the Patriot War contributed to the construction of healthy Anglo-American and Canada–United States relations in the 20th century; it also led, more immediately, to a backlash among citizens regarding the seeming overreach of federal authority, which hurt congressional Democrats in the 1838 midterm elections.