Enumerated
The role that the president plays when he deals with foreign leaders is to negotiate on behalf of a nation. He acts as the representative of the entire nation.
He asked congress to to put a tax on whiskey
No war must be declared by Congress. A formal "announcement" must be made to the international community.
After the Supreme Court's decision on the steel industry, it's decision seemed to declare that all the nation's wisdom did not reside in the chief executive nor the executive branch. With that said, the US Congress asserted itself in foreign aid, where executive policy was entirely dependent on annual legislative appropriations. In this capacity Congress began a more interested party in foreign aid, even in the face of executive opposition. Much Congressional interest, for example became evident in foreign aid to Latin America.
To assert the viabiliy of the Confederacy as a sovereign nation and gain official recognition by Congress and by foreign countries.
The Confederacy considered itself a sovereign nation. Congress did not recognise Confederate sovereignty, and took care not to declare war - which would have been an acknowledgment of this. The Union did not see itself fighting a war with a foreign adversary, but merely putting down a rebellion within its own borders.
Congress makes laws for the nation
Answer 1) He can make executive agreements. this means he can make a deal with another leader of a foreign country, without ever needing approval from Congress. This is different from a treaty because a treaty involves an agreement by all components of a nation's government. 2) He can deploy troops without congress's approval. He can keep them there for 60 days unless congress declares war, or extends the time, under the War Powers Resolution.
England
It goes to congress for approval or not.
If the question is referring to a state in the United States of America, the answer is never. Only the federal government can declare war. However if war occurred in a state in the United State than a state could protect itself with the national guard.
You are reffering to their foreign policy. The foreign policy of a nation depends on the nation and the situation (friendly, hostile, trade discussion, ect,). Some countries respond to situations more hostily than others (example: government A kidnaps a citizen from Government B and C's countries. Governemnt B may respond by asking for them back, but no other acts while C may declare war). This has to do with their foreign policies, previous relations with the other countries, and strength compared to the other nation.