Today on "Special Report"

Carl Cameron reports: Democratic presidential hopeful John Kerry (search) is in command — If he sweeps the South during today's primaries — Who is facing a countdown to the end of their campaign?

"Fox News Sunday" host Chris Wallace will discuss early signs coming from the exit polls.

GUEST PREVIEW: We'll have analysis and assessment of the developing seven state contests with FNC political analyst Susan Estrich.

Brian Wilson reports: Tests confirm that the white powder found yesterday in the mailroom of Senate Majority Leader Bill Frist (search) was indeed the deadly toxin ricin. Was this an act of terror? We'll have the latest.

Jim Angle reports: The United Nations (search) will send a team to Iraq to help its political transition in anticipation of the turnover of power there June 30.

Glen Oglaza reports: British Prime Minister Tony Blair (search) also wants answers about pre-war intelligence. Get a full report.

Details on those stories and more on "Special Report with Brit Hume" at 6 p.m. ET.

— Guests and topics are subject to change