 This drift of 2.9 miles (4.7 km) northward is generally thought to be due to the change in magnetic declination, which he did not correct his compass for as the survey progressed.When Missouri prepared to enter the Union in 1820, various boundaries were discussed before it was finally decided to go with a boundary that had already been formally surveyed and so the Sullivan line was picked.However the Missouri Constitution muddied the debate when with phrase