Just that: approving them.
The Senate has the responsibility of approving treaties.
the US. President approves treaties.
Approving Presidential appointments and treaties
The Senate has the important job of approving treaties made by the president.
The President of the United States is responsible for negotiating and finalizing treaties with other countries. However, the Senate must approve treaties by a two-thirds majority before they can take effect.
Auditor
a: auditor
government is in charge of it
the president is in charge of relationships with other countries.
The Senate is responsible for either approving of a treaty or rejecting it.
No, it cannot. The power to make treaties with foreign countries is expressly reserved to the president under Article II of the US Constitution. The only role Congress plays is that treaties are subject to the advice and consent of the Senate. Note that "Congress", (i.e. the Senate and House of Representatives together) does not have a role in approving treaties. Only the Senate has such a role.