This article was produced by\u00a0ProPublica. Tax evasion is at the center of the criminal cases against two associates of the president, Paul Manafort and Michael Cohen. The sheer scale of their efforts to avoid paying the government has given rise to a head-scratching question: How were they able to cheat the Internal Revenue Service for so many years? The answer, researchers and former government auditors say, is simple. The IRS pursues fewer cases of tax evasion than it did less than 10 years ago. Provided you\u2019re not a close associate of President Donald Trump, there may never be a better time to be a tax cheat. Last year, the IRS\u2019s criminal division brought 795 cases in which tax fraud was the primary crime, a decline of almost a quarter since 2010. \u201cThat is a startling number,\u201d Don Fort, the chief of criminal investigations for the IRS, acknowledged at an NYU tax conference in June. Bringing cases against people who evade taxes on legal income is central to the revenue service\u2019s mission. In addition to recouping lost revenue, such cases are supposed \u201cto influence taxpayer behavior for the hundreds of millions of American citizens filing tax returns,\u201d Fort said. With fewer cases, experts fear, Americans will get the message that it\u2019s all right to break the law. Starting in 2011, Republicans in Congress repeatedly cut the IRS\u2019s budget, forcing the agency to reduce its enforcement staff by a third. But that drop doesn\u2019t entirely explain the reduction in tax fraud cases. Over time, crimes only tangentially related to taxes, such as drug trafficking and money laundering, have come to account for most of the agency\u2019s cases. \u201cDue to budget cuts, attrition and a shift in focus, there\u2019s been a collapse in the commitment to take on tax fraud,\u201d said Chuck Pine, who used to be the third-ranking criminal enforcement officer at the IRS and is now a managing director at BDO Consulting. \u201cI believe there are thousands of individuals who have U.S. tax obligations and are not complying with U.S. tax laws.\u201d The result is huge losses for the government. Business owners don\u2019t pay $125 billion in taxes each year that they owe, according to IRS estimates. That\u2019s enough to finance the departments of State, Energy and Homeland Security, with NASA tossed in for good measure. Unlike wage earners who have their income separately reported to the IRS, business owners are often on the honor system. The IRS declined to comment on its enforcement efforts. Cohen\u2019s and Manafort\u2019s cases illustrate different but common types of tax cheating, and how the IRS has struggled to enforce the law. Cohen failed to report income from domestic businesses. Manafort used exotic foreign locales and shell corporations to hide his money. Cohen\u2019s tax evasion schemes were straightforward. Besides paying off a pornographic movie star and a former Playboy model in violation of campaign finance laws, he pleaded guilty to lying on his tax return. Whether it was income from his business owning taxi medallions, millions of dollars in interest payments on a loan he\u2019d made to another taxi operator or the $30,000 he made by brokering the sale of a luxury handbag, Cohen simply hid the money from his accountant and the government. Over five years, he didn\u2019t disclose $4.1 million, saving himself $1.5 million in taxes. The IRS typically catches such evasion by auditing taxpayers. Theoretically, evidence picked up in audits can be used to start criminal cases. But the rate at which the agency audits tax returns has plummeted by 42 percent since the budget cuts started. Criminal referrals were always rare and are becoming rarer still, dropping from 589 referrals in 2012 to 328 in 2016. With the government conducting 1.2 million audits in 2016, that\u2019s one criminal referral for roughly every 3,600 audits. \u201cThe focus of auditors and tax collectors is not to identify fraud, it\u2019s to collect tax,\u201d said a special agent, who spoke on the condition of anonymity because he was not authorized to speak to the media. Management has set other priorities, he says. \u201cSo by default, the employees are not doing it.\u201d In addition, current and former IRS agents say that audits are not as intensive as they used to be. Because the IRS pushes agents to close audits more quickly, they make fewer requests for records and interviews. \u201cThe quality of those referrals was also down,\u201d said Marie Allen, a recently retired auditor who worked at the IRS for more than 30 years conducting complex financial investigations. \u201cThat is what people popularly think we should be doing, and I\u2019m trying to say it ain\u2019t so.\u201d Budget cuts have diminished the criminal investigation division, trimming the number of agents by a fifth since 2010. Recently, the IRS closed four of its 25 field offices, according to Fort. In New York state, home of the country\u2019s financial industry, the revenue service is down to 161 agents, about a hundred fewer than it had 15 years ago. It doesn\u2019t help that many agents prefer chasing flashier crimes than tax evasion. Rob Warren, a research associate at Catholic University who previously spent a quarter century at the IRS, interviewed 30 former special agents. He asked each agent which of their cases had been their favorite. The answers, Warren said, typically were only tangentially related to taxes. \u201cIt was usually narcotics, Ponzi schemes, some public corruption,\u201d Warren said. \u201cAgents loved Ponzi cases because there was a real victim, an old lady or something like that.\u201d Federal prosecutors seek out special agents for these cases because they are skilled financial investigators. And tax crimes, like failing to declare illegal income from, say, a bribe or cocaine sales, can be easier to prove than bribery or selling drugs. In recent years, the IRS has also been pulled away from classic tax dodging cases by soaring rates of identity theft. IRS management assigned scores of agents to chase perpetrators who used stolen identities to collect tax refunds. One tax fraud hotbed that has been a clear priority of both the IRS and the Justice Department is going after money Americans stashed overseas without reporting it to the federal government. But there are clear reasons that Manafort, who hid his money in places like Cyprus and St. Vincent and the Grenadines, might still have escaped detection. Switzerland has been the Justice Department\u2019s primary target over the past 10 years, an effort that has resulted in settlements with the giant Swiss banks UBS and Credit Suisse, and dozens of smaller institutions. The IRS allowed Americans with foreign accounts to voluntarily disclose them and pay a smaller penalty than they would have had they been caught hiding the information. Some 56,000 people participated, netting the government $11.1 billion. The IRS\u2019s criminal division also brought several cases against people for concealing accounts. For all this success, there has been little change in the amount of wealth stashed overseas. Americans have about $1.2 trillion of personal assets in tax havens, according to data compiled by Gabriel Zucman, an assistant professor of economics at the University of California, Berkeley, and two colleagues. It\u2019s unclear what portion has been disclosed to the IRS. \u201cWhat has happened over the last 10 years is real progress,\u201d Zucman said. \u201cBut what the data suggest is that it has not had a dramatic effect on the amount of offshore wealth.\u201d Money has flowed out of Switzerland and into Asian tax havens like Hong Kong and Singapore. Moreover, the IRS has made little use of new weapons in the fight against wealth hidden overseas. In 2010, President Barack Obama signed a law that was supposed to provide a crucial tool for government auditors and prosecutors. That law, the Foreign Account Tax Compliance Act, required banks with American account holders to report information to the United States. Like employers filing W-2 forms about their workers, these reports would force account holders to come clean. Eight years later, the program is still getting off the ground. Countries around the world have signed agreements, and more than 100,000 foreign banks have sent information to the United States. But \u201cthere is no ongoing compliance impact of the FATCA at this time,\u201d according to a report this year by the inspector general for the IRS. The report found serious problems with the millions of records collected so far. About half of the records, for example, didn\u2019t include identification numbers for the taxpayers, making it difficult to match the accounts with specific individuals. The IRS hadn\u2019t set up a process for using the records. The agency said it was working on such a system. Here, too, the cuts to the IRS\u2019s budget have had an impact. During the Obama administration, the IRS asked Congress for hundreds of millions of dollars to carry out the program, but received nothing. Since Trump took office, the revenue service has stopped asking.