Congress will mark the fifth anniversary of the Sept. 11 attacks with a pre-election agenda focusing on national security-related issues.

Must-do tasks for lawmakers returning Tuesday from a monthlong break are reaching agreement on defense spending, which has gone from about $300 billion before the terrorist attacks to nearly $500 billion, and passing a $32 billion spending bill for the Homeland Security Department.

The House and Senate plan to recess Sept. 29 until after the November election. Any other issues — perhaps immigration or offshore drilling — they take up before then will be colored by the possibility that the election could restore Democrats to power in either or both chambers.

With no chance of completing all the fiscal 2007 spending bills, Congress will have to return in November after the election for what could be a lame-duck session for Republicans.

The habitually slow-moving Senate is going to have to act with uncharacteristic speed. First up this month will be passage of a $468 billion defense spending bill that includes extra money for military equipment and a security fence along the Mexican border.

The Senate Armed Services Committee is trying to coordinate with the administration on legislation to create a new legal system for holding and trying terrorists in the wake of the Supreme Court's rejection of the current military tribunals.

Responding to other court rulings, GOP leaders also hope to put together in the coming weeks a bill establishing new legal status for the National Security Agency's warrantless wiretaps of terrorist suspects.

Also on the agenda are a port security bill and — if House and Sena. In a rare instance of division with House Republicans, Bush has supported a guest worker program and efforts to help the estimated 11 million undocumented immigrants earn legal status.

On another issue with election repercussions, Republicans will try to show they are addressing the high cost of energy by passing a bill expanding offshore drilling for oil and gas.

The Senate, before leaving for the August recess, passed a drilling bill limited to one area in the Gulf of Mexico. A previously passed House bill is significantly broader. Senate Republicans have made clear that, if Republicans want an energy bill before the election, theirs is the only one with a chance of passing.

Among other pending issues:

—Just before adjourning for the recess, Senate Democrats blocked a GOP plan combining a Democrat-backed increase in the minimum wage with a Republican-backed cut in inheritance taxes and renewing popular tax breaks that have expired. Sen. Majority Leader Bill Frist, R-Tenn., may make another shot at it, but it appears only that extending the tax breaks — including for college tuition and business research — will survive in the end.

—With the Senate and House at odds over legislation to address the lobbying and ethics scandals of the past year, House GOP leaders say they will move ahead with changes in House rules making it more difficult to surreptitiously insert pet projects, or earmarks, in legislation.

—House and Senate negotiators will try to work out differences in bills aimed at preventing girls from crossing state lines to get an abortion without parental notification.

—The House and Senate might try to pass legislation giving Vietnam permanent normal trade relations with the United States.