Why did President Bush veto the previous war spending bill?

White House officials have begun talks with Congress on a war spending bill in place of the one President Bush vetoed on Tuesday.
   He rejected it because the Democratic-controlled Congress tried to set a date for American troops to leave Iraq. The bill would have required a withdrawal to begin by October.
   The spending measure totaled one hundred twenty-four billion dollars. One hundred billion of that would have gone to pay for military operations in Iraq and Afghanistan.
   The veto was only the second of Mister Bush’s presidency. The first was last year, to stop Congress from ending his restrictions on federal money for stein cell research.
   On Wednesday, the House of Representatives voted to try to save the war spending bill that the president vetoed. But, as in the case of his first veto, there was not enough support for an override.
   The president met with Democratic and Republican congressional leaders after the House failed to override his veto. He said he was hopeful that an agreement could be reached. And he called for it to be done quickly. Republican leaders said they hope for a new bill by the end of the month.
   The president says it is time to move away from the political battles of recent days. He said three of his top advisers would be working with members of both parties to write an acceptable war funding bill.
   Talks took place on Thursday on Capitol Hill. The two sides agreed to meet again early next week and to keep details of their talks private. But Democratic leaders said they had not agreed to keep any language about troop withdrawals out of a replacement bill.