The IRS is blaming Obamacare for the agency’s poor customer service, with Commissioner John Koskinen telling Congress on Wednesday that he has had to take money away from answering phone calls and instead spend it on technology and personnel to carry out President Obama’s health care law.

Just 43 percent of taxpayers’ phone calls are being answered so far this year. Mr. Koskinen warned that it would get worse without an infusion of money and Americans may start to feel emboldened to cheat on their taxes.

The IRS chief said Congress didn’t provide additional money to prepare for Obamacare and the tax penalty filings that began this year, so he shuffled at least $100 million from user fee funding that had been going to customer service.

“Because of the zero funding for the Affordable Care Act and [the Foreign Account Tax Compliance Act], the only way we could implement those statutory mandates … in the last year was to move a significant part of that support for taxpayer service into the IT accounts,” Mr. Koskinen said.