Illinois lost more residents than any other state in the most recent population estimates from the U.S. Census Bureau.
The loss of an estimated 37,508 people between July 1, 2015, and July 1, 2016, is a big concern in its own right. It will be an even bigger deal when the state loses one seat in Congress during the next national reapportionment. One political analyst thinks the state might even lose two seats.
Illinois has been losing political clout for several decades now. The state had 24 U.S. House districts between 1973 and 1982. That fell back to 22 House districts in 1983 and 20 in 1993. The Land of Lincoln's share of House seats fell to 19 in 2003 and 18 in 2013.
Even if the state records a modest gain in population during the next few years, it is likely that growth elsewhere will result in a smaller Illinois congressional contingent.
Sean Trende, who writes for RealClearPolitics, recently predicted that Illinois will almost definitely lose a House seat in 2023.
"Florida, Arizona and Texas are 'on the bubble' for their 29th, 10th, and 39th seats, while California is close to losing a seat, while Illinois is close to losing a second seat," Trende wrote on the political website.
Reapportionment will occur after the 2020 Census.
Reapportionment and redistricting take place every 10 years after Census counts are completed. This is done to preserve the "one man, one vote" concept spelled out in a U.S. Supreme Court ruling. In essence, the 435 U.S. House seats are allocated to states on a population basis that is designed to keep House district populations fairly even.
Although Illinois remains the fifth most populous state, with Pennsylvania close behind, the most populous states -- California, Texas, Florida and New York -- have been growing or at least not losing population as quickly as Illinois.
Other states along the coasts or in the Sun Belt -- such as Arizona, North Carolina, Oregon -- have been picking up population at a faster clip than states in the Rust Belt.
There has been anecdotal evidence that Illinois has suffered from out-migration for years.
During his campaign for governor, Bruce Rauner said many of Illinois' wealthiest residents had moved elsewhere when the state's income tax went to 5 percent from 3 percent in 2011, even though other states have higher income tax rates.
U-Haul, Allied Van Lines and other moving-truck businesses report high demand for truck rentals headed out of Illinois, but much lower demand for Illinois-bound movers.
IRS statistics from 2013 show the top destinations for people leaving Illinois are Texas, Florida, Indiana, California and Arizona.
There are some data showing that people who depart the state are earning much more than those arriving. Mathematically that's not a complete picture, because economists use the analogy of everybody standing in line and when one wage-earner leaves, someone steps up one spot to take the vacant job. Even if that's overly simple, it makes some sense.
The loss of political might is not theoretical.
If and when Illinois loses another House seat or two, the state will lose an equal number of Electoral College votes, making it less important to presidential candidates. During non-election years, the state will have a more muted voice in big political decisions because there will be fewer lawmakers working on behalf of a particular area of the state.
At the same time there will still be plenty of political clout in Texas, Florida and California, which already look inviting for those seeking warm weather.