Congress has general powers—to “lay and collect taxes,” to draw money from the Treasury, and to “make all laws which shall be necessary and proper”. Congress has broad authority to conduct investigations into particular foreign policy or national security concerns.Furthermore, Congress has the power to create, eliminate, or restructure executive branch agencies, which it has often done after major conflicts or crises.
The President has power to appoint and receive ambassadors flows the implicit authority to recognize foreign governments and conduct diplomacy with other countries generally. From the commander-in-chief clause flow powers to use military force and collect foreign intelligence.