Madison -- The state Senate is about to start its session Tuesday morning amid heightened security.

The senators have not yet arrived for the scheduled 11 a.m. session, but already there is a pack of media on hand and State Patrol troopers outside the chamber and above it in the elevated public galleries.

In a sign of the tenseness of the situation, the guarded door of the Senate chamber was being kept locked and was being opened by a staff member with a key to let reporters and other staff into the chamber.

On Thursday, Democrats in the Senate fled to Illinois to block a vote on Gov. Scott Walker's budget repair bill, which would repeal most union bargaining rights for public employees.

On Tuesday, the Senate will vote on measures to honor the Green Bay Packers and extend an expiring dairy and livestock tax credit. The votes are meant to embarrass absent lawmakers such as Sen. Dave Hansen (D-Green Bay), who wrote the Packers resolution.

Without Democrats present, the Republicans have enough members to be able to vote on measures that don't spend money, but not on fiscal bills such as the budget-repair bill. Twenty senators must be present for spending bills, and Republicans hold 19 seats.

Senate Majority Leader Scott Fitzgerald (R-Juneau) said a bill to require voters to show photo ID at the polls could come up another day soon if Democrats don't return.

As written, the photo ID bill would need 20 senators present because it appropriates money to provide free IDs to those who don't have driver's licenses. But Fitzgerald said the bill could be changed to take out the spending provisions.

The Senate Committee on Transportation and Elections is set to vote on the bill Tuesday. The Senate could then act on the bill as early as Wednesday. Democrats strongly oppose the photo ID bill and would want to argue against it on the floor of the Senate.