Updated

President Obama will be lunching with Senate Democrats tomorrow. One of the topics of discussion - the continuation of the hugely popular cash-for-clunkers program which gives car buyers up to $4,500 for trading in older vehicles for more fuel efficient models.

White House Press Secretary Robert Gibbs hinted the senators might be on the receiving end of a car sales pitch themselves. "I know one of the things that will be discussed is...the president's push to continue the cash-for-clunkers program, which, without some help from the Senate...will likely mean that the program will have to be stopped by the end of the week."

The CARS program, as it is officially known, was so popular that in it's very first week, it nearly ran out of the $1 billion appropriated by Congress to try to spur auto sales (and reduce auto emissions). Before heading into recess on Friday, the House approved an additional $2billion in funding. But the Senate has yet to act.

Gibbs said the president will use the lunch opportunity to highlight the program's benefits for the senators. "It's good for consumers, it's good for dealers and auto manufacturers," Gibbs told reporters at today's briefing. "It's good for our energy security and our environment."

On Friday, after the House acted to funnel more money into cash-for-clunkers, Gibbs encouraged the public to go out and take advantage of the program. Today however, he was much more pessimistic arguing that if the senate doesn't vote by Friday, "I would not give people the same assurances of going into a dealership over the weekend."