It is the extension of the Bush tax cuts.  This is what everything else hinges on.  The Bush tax cuts have eaten the Social Security surplus and threaten to eat everything else up if they are extended.  Making huge annual deficits as far as the eye can see makes for a huge accumulated debt and will seriously restrict choices in teh future, because we will no longer be able to borrow when we need to (such as for the SS bonds in the trust Fund).

The tax measures will be folded into the Budget Reconciliation Bill that will originate in the House AND WILL NOT BE SUBJECT TO A FILIBUSTER IN THE SENATE.  

Right now there are several Repubs who are nervous about the growing debt load. they need to be shored us, as do the Dems.  The most important things are to:

Most important, urge Congress to honestly state the implications of tax and budget cuts, and require an offsetting tax increase ("loophole closing" is their euphemism) for every new or extended tax cut.  This is what is known as the "PAYGO" rule, for Pay-as-you-go, that was in effect when Clinton was President.  The Repubs only want the rule to apply to budget increases, so that tax cuts don't have to be offset and approved by a supermajority.  Also to include the War(s) in the budget.

On taxes, urge that they:

1. Do not extend the cuts on the top two brackets.  These expire in 2008, so there is no need to extend now.

2.  Do not extend the reduction in the tax rate for capital gains and dividends.  These also do not expire until 2008.

3. Do not extend repeal of the estate tax.  This does not kick in until 2009, and does not expire until 2010.  No need to deal with it now.

4.  Keep the 10% bracket and the child tax credit, as well as the earned income credit.

This fight is really the pivot on which everything will be decided, as it will determine how much money is available and who will pay.  It will also determine what kind of flexibility there will be in the future.