WASHINGTON - Senate Democrats, under pressure from party colleagues in the House, agreed Thursday to an economic rescue package that would add checks for Social Security retirees and disabled veterans but leave out extended jobless benefits and additional business subsidies. The package would rush tax rebates of $500 for individuals and $1,000 for couples to most taxpayers and grant business tax cuts to revive the economy. Leaders in both parties and in both chambers of Congress had agreed by Wednesday night on the idea that 20 million seniors whose sole or main income is Social Security and 250,000 veterans living...