Why should the U.S become less dependent on fossil fuels?

WHY? Our political and economic stability depends on the provision of half our oil from other countries, many of which are either unfriendly or openly hostile to the US. Eliminating the control of others on our actions and economy is a good idea for obvious reasons. besides, all that money we send off shore is used to fund things (like terrorism and anti-american propaganda, development of weapons in unfriendly nations) that are really not in the best interests of a free society.