Is Bush stepping outside of his powers by making this deal with Maliki?

A deal setting the foundations for what could be a long-term presence of US troops in Iraq has been signed by the US president and Iraq's prime minister.

George Bush and Nouri al-Maliki signed a "declaration of principles" on Monday that will guide talks next year on reaching agreements covering a long-term relationship between the two states.

"The size and shape of any long-term ...presence in Iraq, will be a key matter for negotiation between ... Iraq and the United States," Lieutenant-General Douglas Lute, the White House deputy national security adviser, said.

Lute's remarks were notable in that top US officials, beginning with Bush, have repeatedly denied seeking permanent bases in Iraq or that the US deployment was open-ended.

http://english.aljazeera.net/NR/exeres/817CBD8C-DBCF-40E5-857C-C50E8B0F41E0.htm

I'm not sure, but I think this sort of thing usually needs Senate approval.

and the permanent bases, would need Senate approval - it would be a treaty. But this looks like the agreement to negotiate the treaty - 'a "declaration of principles" ... that will guide talks next year on reaching agreements'.