Like everything else Congress does, an official recess requires a piece of legislation. Under the Constitution, if the Senate wants to adjourn for more than three days, then it needs approval from the House of Representatives.
The House, however, has already taken its July 4th recess, and House Republicans have left town without approving an adjournment resolution for the Senate. As a result, the Senate is expected to enter a "pro forma" session next week -- a step that rules out possible recess appointments.
Of course, this is the whole point. Even though President Obama has shown little willingness to make recess appointments, Republicans are still wary of an attempt to recess appoint controversial figures like Elizabeth Warren. Republicans in both chambers have urged House Speaker John Boehner to refuse authorization for a Senate recess, and for the second time (the first was for the Memorial Day recess), Boehner obliged.
Some argue it is possible for President Obama to force a recess; under Article II, Section 3 of the Constitution, the president
">could theoretically adjourn
either chamber of Congress in the event of disagreement between them. But it's never been used before in this way. The last time the power in that section were used at all was when President Harry Truman called Congress into a special session in 1948. Using it now could detonate negotiations on the debt ceiling, and damage the administration's position on other issues. As such, Democrats have been quiet on the option, and the White House doesn't seem interested either.