Why is the GOP opposing closing tax havens for tax cheats?

The Obama administration is proposing to close offshore shelters for tax cheats. For some strange reason GOP members of congress are fighting the proposal. Is there some reason why CITI Bank, who has taken billions in bailout money from the government should run 99 offices in Malaysia in order to shelter taxable income? Why is the GOP opposed to legislation to close these tax loopholes for tax cheats? Are they just catering to their base, tax cheats and religious freaks?