One of the main reasons President Clinton found it difficult to lower the budget deficit was because of political opposition from Republicans in Congress. Clinton's efforts to reduce the deficit often faced resistance from Republicans who were opposed to his proposals, such as raising taxes on the wealthy. Additionally, Clinton faced challenges in reducing spending on entitlement programs such as Medicare and Social Security, which were popular among voters. Despite these challenges, Clinton was able to work with Congress to pass the Omnibus Budget Reconciliation Act of 1993, which helped to reduce the deficit.