As Democratic Senatorial Campaign Committee Chairman Charles Schumer (N.Y.) makes his final push to secure a 60-vote majority in the chamber and Republicans work to minimize their losses, the halls of the Senate have fallen eerily quiet as lawmakers and staff have emptied out onto the campaign trail.

Four days before the elections, most offices in the Senate are operating with little more than skeleton crews. Most of the top staff for Senate Minority Leader Mitch McConnell (R-Ky.) and Republican Conference Chairman Lamar Alexander (Tenn..) have been back in their bosses’ home states for weeks. Both McConnell and Alexander are facing voters this year, with McConnell locked in a tight fight and Alexander expected to see a relatively easy win on Election Day.

Aides for Democratic incumbents such as Sens. Mary Landrieu (La.) and Tim Johnson (S.D.) have also taken time off from their Senate jobs to work or volunteer for their bosses’ campaigns.

Much of the staff for lawmakers not in cycle have also been dispatched to the trail, either to Senate campaigns or to the presidential campaigns of Sens. Barack Obama (D-Ill.) and John McCain (D-Ariz.).

For instance, Rodell Mollineau, a top strategist to Majority Leader Harry Reid (D-Nev.), has taken time off in Alaska to help Anchorage Mayor Mark Begich’s (D) campaign against recently convicted Sen. Ted Stevens (R). Other Democratic leadership aides on leave from their official duties have been dispatched by Obama’s campaign or the Democratic National Committee to battleground states such as Pennsylvania.

Meanwhile, DSCC Communications Director Matt Miller is headed out on a last-minute tour of states, Democratic sources said on Friday. Miller, who was in Alaska Friday afternoon, is expected to hit several more states featuring top Senate races before Election Day.