President Clinton's senate trial began today when senators took their oaths as jurors. They'll meet behind closed doors tomorrow morning to work out the impeachment trial ground rules. As with the House several weeks ago, the Senate is receiving an unusually high volume of constituent e-mails. The senate computer server is handling seven times the usual number of messages. Republican Rod Grams' office is getting about a thousand constituent comments per day--that includes phone calls, e-mails and letters. Grams' press secretary says constituent feedback is running 2-to-1 against the President, and most people also oppose censure. Democrat Paul Wellstone's office didn't have exact numbers, but said the Minnesota office got fewer calls than expected, and constituents were evenly split on removing the president from office.