Many analysts say the president and Congress could send a strong signal to global markets by agreeing this year to a package of both long-term tax increases and spending reductions, especially in the popular entitlement programs, that would not take effect until 2012. That is the recommendation of two new studies, one from a diverse group sponsored by the National Academy of Sciences and a separate joint project of the Peter G. Peterson Foundation, the Pew Charitable Trusts and the Committee for a Responsible Federal Budget. ...