Since Marokai has not posted in the last seven days, I would think we ought to declare him "absent". In the case of the PPT's absence, his duties may be performed by the district senator serving the most consecutive terms. In this case that's Yankee. Yankee is by senate rules the acting PPT unless either he declines to take up the PPT duties or Marokai returns. If Yankee declines the responsibilities, the next in line would be MOPolitico.
I can run the Senate for now, however there is a slight problem. MB only became PPT again two days ago, and the OSPR specifies a five day absence for the Senate Dean to be able to run the Senate on the basis of such an absenteeism. One would assume that would have to be a complete five days absent "as PPT". I shall rely on the VP to sanction my actions in that case. He is also capable of managing the Senate to any extent he desires, regardless of the PPT's presence or absence, as well.
