What is an example of how thomas jefferson’s political views changed after he became president? he completed the louisiana purchase despite there being no provision for doing so in the constitution, thus expanding the power of the president, but before he believed only powers listed in the constitution can be used (constructionist). he gave up all his slaves because he realized that slavery was wrong. he wanted to restrict further trade with england because the cotton gin was america. his stand on states' rights prevented him from adding to the territories belonging to the united states.