The 2020 census was supposed to be the decennial survey that finally embraced technology, a much-needed victory for the U.S. Census Bureau that, about a decade ago, suffered a costly setback in its attempt to modernize.

However, the agency is in danger of repeating the past by conducting the census the old-fashioned way, with pencil and paper.

Last week, the Commerce Department announced that the Census Bureau, the agency charged with collecting data about the American population, will soon be without its top official. Director John Thompson, who has led the agency since 2013, will leave the Census Bureau on June 30. His five-year term was slated to end in December.

The timing of his early departure is problematic as testing for the 2020 population survey begins in August. Thompson's exit leaves "a real leadership vacuum" at the Census Bureau, said Phil Sparks, a former census official who is now co-director of the Census Project, an advocacy group in Washington, D.C. He told the Washington Examiner that it typically takes about six months for a replacement to be chosen and go through the nomination process and that it's "not going to help" the agency if it lacks the "political clout" of its top advocate on Capitol Hill when the budget process for fiscal 2018 ramps up this year. An acting director will step in once Thompson departs, but it's not yet clear who that will be.

The Census Bureau is already facing the increasingly onerous task of making the 2020 decennial head count the first to rely primarily on the Internet and IT services. Thompson raised red flags last week when he told lawmakers during a hearing that the agency's new IT system, the Census Enterprise Data Collection and Processing (CEDCaP), is now expected to cost more than $300 million above the original estimate of $656 million, a jump of nearly 50 percent.

The agency's technology woes now are uncomfortably reminiscent of the problems it faced 10 years ago. Technical issues and delays during the 2008 test phase led the Census Bureau to abandon its push for census takers, who are sent out to collect data from people who didn't submit mail-in forms, to use handheld devices that could verify street addresses with GPS software in favor of relying on a paper, pencil and clipboard. This setback cost the agency an extra $3 billion.

Now members of Congress and watchdog groups are concerned about a 2010 census repeat.

"It's distressing to see the 2020 Census look like it's going the same direction as the 2010 Census," said Rep. John Culberson, R-Texas, and chairman of the House Appropriations Subcommittee for Commerce, Justice, Science and Related Agencies, at a recent oversight hearing on the 2020 census.

Each decennial survey, which is mandated by the Constitution and is used to reapportion seats in the U.S. House of Representatives and state legislatures, is more expensive than the last as the U.S. population rises and demographics change. The census cost $9.4 billion in 2000 and $12.3 billion in 2010, in 2020 dollars, and the cost of counting each housing unit has ballooned from $16 in 1970 to about $92 in 2010, in constant 2020 dollars, according to the Census Bureau.

CEDCaP is one aspect of the Census Bureau's push to modernize, which also includes allowing U.S. citizens to complete the survey online or by phone, providing mobile devices for field enumerators and streamlining field operations. The IT push would digitize much of the data collection process and help supplement information on U.S. citizens from other government agencies.

Thompson said the IT upgrade would "cost far less than repeating the outdated processes used in 2010" and would save $5 billion, containing the cost of the 2020 survey to $12.5 billion, a mere $200 million more than in 2010. A new cost estimate is expected this summer, but officials from the Government Accountability Office, as well as the Commerce Department Office of Inspector General, expect the bill to get higher.

In a recent report, the GAO praised the Census Bureau's innovations as showing "promise for controlling costs," but also cautioned that they "introduce new risks" due to a lack of testing of nearly half of its 50 IT systems. This year, GAO dubbed the 2020 census a "high-risk" government program because of its rising costs and IT issues. "Since 2014, GAO has made 30 recommendations related to this area; however, only 6 have been fully implemented as of January 2017," the report notes. The 2010 census was also deemed "high-risk" in the years leading up to it.

A key field test set to begin in August, the 2018 End-to-End Census Test, will take place at 700,000 households in Rhode Island, Washington state and West Virginia and will help the Census Bureau determine its readiness and plan for 2020.

Questions about CEDCaP's success weigh on the agency as it also faces a budget crunch. In April, Congress approved a $1.47 billion budget for the Census Bureau for fiscal 2017, and the Trump administration's proposal for fiscal 2018 calls for $1.5 billion for the Census Bureau's 2020 effort, which experts and advocates worry may be inadequate.

"If not properly funded, this is not going to be an accurate census," Sparks warned. The Census Bureau has already had to make adjustments over funding concerns. For instance, last year the Census Bureau canceled field tests and delayed the opening of field offices due to uncertainty over funding in Congress.

Sparks said providing a boost to the 2020 census effort could be an easy win for President Trump in a tense political climate or that it could look bad if he doesn't ensure adequate resources are provided. Asked if he had a message for Trump, Sparks' reply was: "You own the census for 2020."