Zero. At most nearly zero.
But it doesn’t matter as it only takes a simple majority in the House to impeach.
Rosenstein has angered the majority in the House of Representatives.
That's true, but I was discussing Congress's unwillingness to defend its institutional privileges, which are actually OUR privileges to govern ourselves, DELEGATED to them in Article I.
Congress cannot function as intended if the party in the minority seeks to govern through the Executive, or through the courts.
And, of. course, a party line impeachment of Rosenstein would be worse than useless, and could cause great harm, as the impeachment of Clinton did.