State legislatures could (and should have a lot to do with the Middle East and Ukraine.
It is true that States play no part in carrying out our constitutional foreign policy powers. They are prohibited, by Art. 1, Section 10, from entering into "any alliance, treaty or confederation . . ." Article 1, Section 8 gives Congress alone the power to declare war. Article II gives the Senate the final say on treaties negotiated by the president. Nevertheless, the state legislatures (collectively) could have a great deal to do with both foreign and domestic policy. This is because they have the final say on constitutional amendments. Since our Constitution establishes how our federal government organizes and carries out all its powers, the state legislatures have the power to affect all aspects of government. However, they have not yet chosen to use this power.
Article V connects the states to foreign policy
Article V gives the state legislatures (collectively) the final say in calling conventions to propose amendments to the Constitution and in ratifying proposed amendments. As to the calling of conventions, Article V reads, in part," . . . on the application of the legislatures of two thirds of the several states, (Congress) shall call a convention for proposing amendments . . . " As for the final approval of proposed amendments, Article V says that the proposals "shall be valid" when ratified by "the legislatures of three fourths of the several states or by conventions in three fourths thereof, as the one or the other mode of ratification is proposed by the Congress."
It is clear from Article V that the state legislatures have the option of either making the final decision themselves or delegating it to state conventions formed for that purpose. It is true that the language is ambiguous. That is, the use of the word "shall" is not consistent with the use of the word "proposed." However, this ambiguity is resolved by two considerations.
First, the imperative connotation of the word "shall" applies only to validity. The last phrase of the sentence appears to be an "add on" for the sole purpose of establishing the validity of both methods of ratification. Second, there is a general rule that a word used twice in the same provision has the same meaning in both cases. For example, Article I give the House the "sole" power to impeach and the Senate the "sole" power to try all impeachments. Since the word clearly means "exclusive" in one case, it also means "exclusive in the other. Since the word "propose" clearly means "suggest" in the opening sentence of Article V, it also means "suggest" later on. Third, there was a perceived need in the 1787 convention to provide for the sovereignty of the states and a general fear of allowing Congress to play a substantive role in the amendment process. It would, therefore, seem unlikely that the Framers intended to give Congress this procedural control.
The 10 th Amendment connects thrr states to foreign policy
This Amendment reads, "The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people." The power to ratify constitutional amendments is neither delegated to the United States nor prohibited to the states. Rather, it is delegated to the states explicitly or to the people if the state legislatures should so choose." There is no question that the state legislatures have the power to shape the way the US makes policy.
The role of Congress
Neither is there any question but what Congress has, by its inaction, forestalled the calling of a constitutional convention. Such a convention would no doubt place before the states proposals to "new model" our powers of government. For example one set of pending state applications aims at a considering a balanced budget. Another set aims at overturning the Citizens United Supreme Court decision.
The Framers anticipated Congress playing a role. For example, Col. Mason declined to sign the proposed constitution, largely because, if amendments were proposed by Congress, ". . . no amendments of the proper kind would be obtained by the people, if the government became oppressive as he verily believed would be the case."  Madison, in Federalist 53, expressed pride in the fact that our Constitution would be "unalterable by the government." He later opened the door to by-passing Congress when he said that he saw no reason why Congress should not be bound to propose amendments to the several states without a convention "on the like application" by two thirds of the states.