As the GOP celebrates its tax victory, the IRS is gearing up to carry out and enforce the changes to the tax code. As the agency processes millions of 2017 tax returns, it will simultaneously have to interpret and implement a new system for 2017.

In the coming months, the agency will have to explain new statutes and changes in current law to businesses, individuals, and tax preparers. Before the start of filing season, it will have to update tax forms, which is a monumental undertaking due to the agency’s outdated technology. During tax filing season, the IRS will have to answer questions from taxpayers and practitioners about the changes to the tax code. This task will be difficult without adequate personnel and funding,

In addition to dealing with the new tax law, the IRS must balance other priorities, including the president’s May 2017 executive order mandating all federal agencies to meet certain cybersecurity requirements. Due to funding shortages, the IRS may not be able to meet its deadlines to update internal systems and implement other changes to existing infrastructure.

Prior to leaving the agency, former IRS Commissioner John Koskinen warned that years of cuts to the agency’s budget will make it difficult for the IRS to carry out its mission. Since 2010, the IRS’ budget has been cut by $900 million and its staff has been reduced by 23 percent.

The Senate’s FY 2018 Financial Services spending bill would provide $11 billion for the IRS. Of the new topline amount for the agency, approximately $5 billion would be for enforcement, another $4 billion would go towards operations support, and $2 billion is reserved for taxpayer services.

The FY 2018 funding levels reflect a $120 million cut from FY 2016 funding levels, which was the last time Congress passed an appropriations bill.

With a spending bill looming, congressional Republicans must now decide whether it will increase funding for an agency that many in the party have criticized for years. If Congress fails to increase funding for the agency, the consequences may be catastrophic. The IRS has warned that without additional funding, the agency could be vulnerable to a major security breach or failure during tax season.