For each decade that Illinois has been a state, here are 20 defining moments in Illinois political history

Ten score years ago, on December 3, 1818, Illinois became the 21st state to be admitted to the Union. Now, with the great State of Illinois celebrating its 200th birthday, here are 20 of the most defining moments in Illinois political history, one for each decade that Illinois has been a U.S. state (although not all decades are represented, and some are represented more than once) and presented in chronological order:

1. Illinois's admission to the Union - During much of the year 1818, what was then the Illinois Territory went through a lengthy process to become what is now the State of Illinois. On April 18, 1818, the U.S. House of Representatives was officially notified that President James Monroe had signed an Act of Congress titled "An Act to Enable the People of Illinois Territory to form a constitution and state government and for the admission of such state into the Union on an equal footing with the original states" into law. In July of 1818, delegates to a state constitutional convention were elected, and, after Illinois's first state constitution was ratified, Congress passed the Illinois statehood resolution on December 2, 1818, which was signed into law by Monroe the following day, December 3, 1818.
2. Springfield becomes Illinois's capital city - Springfield was not the original capital city of the State of Illinois. For the first year or so of Illinois's statehood, Kaskaskia was the state capital. For two decades, Vandalia was Illinois's capital city. In 1839, the seat of Illinois's state government was moved from Vandalia to Springfield, where it remains to this day.
3. The Mormon War - During the mid-1840's, Nauvoo, located on the Mississippi River in west-central Illinois and then home to a large Mormon population, was home to nearly as many people as Chicago was home to at the time. In January of 1845, Nauvoo was disincorporated by the Illinois General Assembly with the support of the non-Mormon population in the areas around Nauvoo, and, after a succession crisis within The Church of Jesus Christ of Latter-Day Saints, a de facto Mormon theocratic government led by Brigham Young gained control of Nauvoo before the Mormons were forcibly expelled from Nauvoo, with the Mormons resettling in what is now the State of Utah.
4. The Lincoln-Douglas Debates - In 1858, Republican Abraham Lincoln and Democrat Stephen Douglas participated in a series of seven debates as part of their campaigns for one of the state's U.S. Senate seats. At the time, Illinois did not hold direct elections for U.S. Senate, and the Illinois General Assembly elected the state's U.S. Senators. Democrats won control of the General Assembly in the 1858 state legislative elections, and Douglas was elected to the U.S. Senate by the General Assembly, although Lincoln became a rising star in American politics through his debate performances.
5. Abraham Lincoln's election to the U.S. presidency - In 1860, Republican Abraham Lincoln of Springfield was elected president. Perhaps the single greatest individual to have ever called Illinois home, Lincoln led the United States during the Civil War and is widely credited with keeping the United States whole. To this day, one of Illinois's many nicknames is the "Land of Lincoln".
6. The Edwards Law - In 1889, the Edwards Law, which required public and parochial schools in Illinois to teach students in the English language and only the English language, was enacted. Public backlash against the Edwards Law, most notably from the German-speaking community in Illinois, played a role in in Illinois, then typically a Republican stronghold, electing a Democratic governor, John Peter Altgeld, in the 1892 gubernatorial election, and, that same year, Democratic President Grover Cleveland carried Illinois on the way to winning a second non-consecutive term in the White House.
7. The Pullman strike - On May 11, 1894 in what was then the unincorporated company town of Pullman (now part of the City of Chicago), employees of the Pullman Company, which manufactured railroad cars, launched, in response to the Pullman Company lowering wages but refusing to lower rents, a wildcat strike against the Pullman Company that turned into a much larger labor dispute throughout much of the country. Then-President Grover Cleveland intervened in the strike on the side of the rail industry, sending armed forces to stop strikers from obstructing rail lines.
8. Chicago becomes a Democratic stronghold - Prior to the Great Depression, Chicago and Cook County were usually Republican strongholds. In 1931, Democrat Anton Cermak defeated Republican incumbent and Al Capone crony William Hale "Big Bill" Thompson to win the Chicago mayor's office, an office that has been held continuously by Democrats (although Chicago mayoral elections are officially non-partisan nowadays, every Chicago mayor since Cermak has been a known Democrat) ever since. Thompson was defeated in large part due to large-scale public backlash against the Republican Party during the Great Depression, growing discontent with rampant organized crime in Chicago, and voters tiring of Big Bill's political antics.
9. "Dewey Defeats Truman" - Even though Democratic President Harry Truman carried Illinois en route to a surprise victory in the 1948 U.S. presidential election, the Chicago Tribune published a post-election newspaper that year that erroneously proclaimed that Republican challenger Thomas Dewey had defeated Truman. To this day, the infamous "Dewey Defeats Truman" headline is considered one of the worst errors committed by the news media in U.S. history.
10. The 1968 Democratic National Convention - Held in Chicago, the 1968 Democratic National Convention, which nominated Hubert Humphrey of Minnesota and Edmund Muskie of Maine for president and vice president, respectively, was marred by anti-Vietnam War protests and what was described in a report to the U.S. National Commission on the Causes and Prevention of Violence as a police riot that took place in front of the Hilton hotel in Chicago on August 28, 1968.
11. Illinois fails to ratify the Equal Rights Amendment - Although Illinois did eventually ratify the proposed Equal Rights Amendment to the U.S. Constitution in 2018, long after the deadline for ratification had passed, the Illinois General Assembly failed to ratify the proposed Equal Rights Amendment before either the original 1979 deadline for ratification or the revised 1982 deadline for ratification. In 1980, the Equal Rights Amendment fell five votes short of the number of votes needed in the Illinois House of Representatives to pass a resolution to ratify the Equal Rights Amendment. Far-right activist Phyllis Schlafly, who unsuccessfully ran for a U.S. House seat in Illinois in 1952, played a major role in the defeat of the ERA.
12. Ronald Reagan's election to the U.S. presidency - In the 1980 U.S. presidential election, Republican Ronald Reagan, born in Tampico, Illinois, defeated incumbent Democratic President Jimmy Carter to win the presidency. Reagan's victory ushered in a conservative era in American politics, with much of Reagan-era policy, particularly in regards to taxes, playing a significant role in increased income inequality in America.
13. The Cutback Amendment - On the same day as the 1980 presidential election, voters in Illinois voted to amend the Illinois Constitution to cut the size of the Illinois House of Representatives from 177 members to 118 members and replace cumulative voting by legislative district with single-member representative districts.
14. The LaRouche movement and the Solidarity Party - In the 1986 Democratic primaries, Mark Fairchild and Janice Hart, two members of the Lyndon LaRouche-led political cult, won the Democratic nominations for lieutenant governor and secretary of state, respectively, in Illinois. The surprise victories of the LaRouche movement came as a very unpleasant surprise to Democrats in Illinois; gubernatorial nominee Adali Stevenson III refused to campaign with the LaRouche-aligned candidates, withdrew his Democratic nomination, and was nominated by the newly-created Solidarity Party for governor. Stevenson III lost to incumbent Republican Governor James "Big Jim" Thompson.
15. Carol Moseley Braun's election to the U.S. Senate - In the 1992 Democratic primary in Illinois, Carol Moseley Braun defeated incumbent U.S. Senator Alan Dixon for re-nomination. Moseley Braun defeated Republican candidate Richard Williamson in the general election, and, by doing so, Braun became the first black woman, and the first black Democrat, to be elected to the U.S. Senate from any state, as well as the first woman and first person of color to be elected to the U.S. Senate from Illinois.
16. The licenses-for-bribes scandal - In 1994, Scott Willis was driving his family's minivan in Wisconsin when the taillight assembly of a semi truck, whose driver had received an Illinois drivers' license through a system of bribery in the office of then-Illinois Secretary of State George Ryan, fell off of the truck and punctured the Willis family's minivan, causing the minivan to burst into flames and killing six children. It was later discovered that a much larger scheme of political corruption existed in Ryan's office when he was secretary of state, which eventually resulted in Ryan, after having been elected governor for one term, receiving a federal prison sentence.
17. Barack Obama's election to the U.S. Senate - At the 2004 Democratic National Convention in Boston, Massachusetts, then-Illinois State Senator and U.S. Senate candidate Barack Obama gave the convention's keynote speech, which was widely seen as the major highlight of that convention and made Obama a rising star in American politics. Obama defeated Republican candidate Alan Keyes in a landslide to win the open U.S. Senate seat.
18. Barack Obama's election to the U.S. presidency - In 2008, Democrat Barack Obama of Chicago was elected President of the United States, defeating Republican candidate John McCain amid a global economic and financial crisis that imperiled the country's economy. Obama became the first person of color to be elected to the nation's highest office. As President, Obama was credited for saving the country's economy and expanding health care access to millions of Americans.
19. The Rod Blagojevich scandal - Not long after Barack Obama's election to the U.S. presidency, then-Illinois Governor Rod Blagojevich was indicted on federal criminal charges related to, among other things, an attempt to sell the appointment to the U.S. Senate seat that Obama was vacating in order to take the office of President, making Illinois the laughingstock of the nation. Blagojevich became the only governor in Illinois history to be removed from office in an impeachment trial, and, on this state's 200th birthday, Blagojevich is currently serving a federal prison sentence.
20. Illinois becomes a marriage equality state - On November 20, 2013, over a year and a half before the Obergefell v. Hodges U.S. Supreme Court ruling making marriage equality law of the land nationwide, then-Illinois Governor Pat Quinn signed into law legislation giving same-sex couples in Illinois the same right to marry that heterosexual couples have long enjoyed, with the law going into effect the following year.