By Sister Simone Campbell – 12/01/14 06:50 PM EST

President Obama’s threat to veto Congress’s new pro-corporate tax deal is the right response. This deeply flawed agreement would permanently extend expensive tax breaks for business while ignoring tax credits for families living in or near poverty.

I have spoken with hundreds of people struggling to raise their families on low wages. Millions of these families would be harmed by the deal. Announcing it just before Thanksgiving, the quintessential family-focused holiday, is ironic, but it would be wrong at any time of the year.

The deal is evidence of deeply flawed priorities. It ignores the Child Tax Credit and Earned Income Tax Credit, despite the fact that they have long received bipartisan support because they are widely viewed as very effective ways to keep people out of poverty. Because of these credits, millions of families are more economically secure and able to further contribute to our economy. In short, they make our entire nation stronger. Despite their proven worth, however, the current deal does not expand the credits or make them permanent.

The Center on Budget and Policy Priorities reports that a single mother with two children who works full time for minimum wage — earning a paltry $14,500 — could lose her entire Child Tax Credit of $1,725 should the credit be allowed to expire in 2017. Meanwhile, the tax deal would let already wealthy corporations continue to reap the benefits of costly tax breaks.

The effects of this poorly conceived agreement would be felt by our entire nation. It would add more than $400 billion to our budget deficits over 10 years because there are no requirements that costs of the business tax breaks be offset. When Congress returns to its cost-cutting ways, it is inevitable that highly paid corporate lobbyists will protect their clients, while vulnerable low-income Americans pay the price. Again.

Obama must veto this deal if it moves forward as is. But the discussion should not end there. Congress should change course to create a balanced, fair tax system that does not focus on enriching those already doing well. Putting money in the hands of low-income people with pent-up demand is both the right and smart way to move forward. This means a permanent, expanded Child Tax Credit and Earned Income Tax Credit.

Tax policies for the 100 percent will make us a stronger nation. Our country deserves and must demand strong leadership, so that will happen.

Campbell is executive director of NETWORK: A National Catholic Social Justice Lobby, and author of A Nun on the Bus: How All of Us Can Create Hope, Change and Community.