And I welcome you to the first of the 2004 presidential debates between President George W. Bush, the Republican nominee, and Senator John Kerry, the Democratic nominee.

These debates are sponsored by the Commission on Presidential Debates.

Tonight's will last 90 minutes, following detailed rules of engagement worked out by representatives of the candidates. I have agreed to enforce their rules on them.

The umbrella topic is foreign policy and homeland security, but the specific subjects were chosen by me, the questions were composed by me, the candidates have not been told what they are, nor has anyone else.

For each question there can only be a two-minute response, a 90- second rebuttal and, at my discretion, a discussion extension of one minute.

A green light will come on when 30 seconds remain in any given answer, yellow at 15, red at five seconds, and then flashing red means time's up. There is also a backup buzzer system if needed.

Candidates may not direct a question to each other. There will be two-minute closing statements, but no opening statements.

There is an audience here in the hall, but they will remain absolutely silent for the next 90 minutes, except for now, when they join me in welcoming President Bush and Senator Kerry.

(APPLAUSE)

LEHRER: Good evening, Mr. President, Senator Kerry.

As determined by a coin toss, the first question goes to you, Senator Kerry. You have two minutes.