Under pressure to take action on rising gasoline prices, President Obama wants Congress to strengthen federal supervision of oil markets, increase penalties for market manipulation and empower regulators to increase the amount of money energy traders are required to put behind their transactions. The White House plan, which Obama was to unveil Tuesday, is more likely to draw sharp election-year distinctions with Republicans than have an immediate effect on prices at the pump. The measures seek to boost spending for Wall Street enforcement at a time when congressional Republicans are seeking to limit the reach of federal financial regulations.