The Case for a Nonpartisan All Candidate Primary in Illinois
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by: Richard Graves, March 18th, 2026
Richard Graves is a writer and independent scholar examining governance, institutional legitimacy, and social outcomes.
Illinois should abandon its current partisan primary system and adopt a nonpartisan all candidate primary, in which every voter receives the same ballot, every candidate appears on the same ballot regardless of party, and the top two, or in a stronger reform model, the top four candidates advance to the general election.
Why?
Because Illinois’s current system permits a form of strategic manipulation that can undermine honest representation.
Illinois’s Current Primary Structure Creates an Opening
for Strategic Crossover Voting
Under Illinois law, established political parties nominate most state, county, congressional, judicial, and many local candidates through the partisan primary system set out in Article 7 of the Illinois Election Code (10 ILCS 5/7-1 et seq.). Illinois voters are not permanently locked into party registration in the same manner as some other states. Instead, in a primary election, a voter requests the ballot of a particular party for that election, meaning the operative partisan choice is made at the time of voting rather than through a durable party registration mechanism (Illinois State Board of Elections, n.d.; Illinois General Assembly, n.d.). That structural feature matters.
It creates an opening for strategic crossover participation, meaning voters may choose the opposing party’s primary ballot not because they identify with that party, but because they believe they can influence which opponent emerges for the general election. Political science literature has long recognized that open or more permeable primary systems can create opportunities for strategic voting by nonparty voters, even if the frequency and practical effect vary across jurisdictions and election cycles (Chen & Yang, 2002). That creates a perverse incentive.
If Democratic voters can walk into a Republican primary and help nominate the Republican they believe their side can most easily defeat in the general election, or if Republicans can attempt the same maneuver on the Democratic side, then the system is not necessarily producing the strongest nominees. It may instead produce the nominees the opposing side believes are most vulnerable. The political science literature has long recognized that open or more permeable primary systems can create opportunities for strategic voting by nonparty voters, even if the frequency and effect size vary across contexts (Chen & Yang, 2002).
That is not the cleanest expression of democratic competition. It is tactical ballot manipulation made possible by institutional design.
A Nonpartisan All Candidate Primary Eliminates the Most Obvious Form of Primary Raiding
A nonpartisan all candidate primary would end that particular game. If every candidate, Republican, Democrat, independent, or otherwise, appears on the same ballot, there is no separate Republican primary to raid and no separate Democratic primary to sabotage. Voters are simply choosing from the full field, and the strongest candidates, not the most strategically vulnerable partisan nominees, move forward.
As scholars examining the California and Washington top two systems note, the defining institutional feature of this reform model is that all candidates appear on a single ballot, all voters may choose among them, and the top finishers advance regardless of party (McGhee & Shor, 2017; Patterson, 2020; Sinclair, 2025). That is a cleaner system. More importantly, in Illinois, it is a more honest one.
Why This Reform Is Stronger for Illinois
1. It reduces partisan sabotage
No voter can “cross over” to game the other side’s nomination because there is only one nomination ballot. The structural opportunity for classic primary raiding disappears because there is no separate partisan contest to infiltrate.
This is the clearest and strongest argument for reform in Illinois.
The literature on strategic voting in open primaries supports the logic that when separate party ballots exist, crossover incentives can emerge. When those ballots are collapsed into one all candidate field, that particular mechanism is eliminated (Chen & Yang, 2002; McGhee & Shor, 2017).
2. It rewards broader appeal from the outset
Candidates in a nonpartisan all candidate primary must compete before a broader electorate from the beginning, not merely before the most committed activists of one party.
Reform advocates have long argued that this can push candidates toward a wider coalition because the median voter in a broader primary electorate is often closer to the general election electorate than the median voter in a closed, or functionally partisan, primary (McGhee & Shor, 2017). Experimental work on California’s 2012 top two primary found some evidence that opening participation can improve representational alignment, although the effects are not automatic and depend heavily on voter information, candidate supply, and the political context of the race (Ahler et al., 2016).
That is the correct scholarly claim.
Not that moderation is guaranteed, but that the selectorate changes, and when the selectorate changes, the incentive structure changes.
3. It can weaken extremist incentives, though not automatically
Under partisan primaries, candidates often have incentives to appeal first to a narrower, more ideological selectorate. Scholars have argued that low turnout primaries can empower more partisan and ideologically intense voters relative to the broader November electorate (McGhee & Shor, 2017; Ranney, 1972).
At the same time, the best scholarship does not support the simplistic claim that primaries alone cause all polarization. Woon (2018) finds that primaries can generate either greater extremism or greater moderation depending on candidate and voter beliefs, while Masket (2019) cautions that primary reform by itself is unlikely to solve polarization absent broader structural changes.
Accordingly, the strongest and most defensible claim is not that a nonpartisan primary will magically eliminate extremism. It is that it changes the front-end incentives by forcing candidates to compete in a broader arena rather than inside a single party silo (Woon, 2018; Masket, 2019).
That is a serious institutional argument, not a utopian one.
4. It can produce more honest general elections, though with real tradeoffs
Instead of voters facing nominees who may have been artificially elevated through partisan gamesmanship, they face the candidates who performed best in a shared statewide or district-wide contest. That is normatively attractive because it better reflects direct performance before the full electorate participating at the primary stage.
However, the evidence also shows that top two systems create tradeoffs.
For example, when two candidates from the same party advance, some voters may “roll off” and skip that race in November, especially if they feel unrepresented by the partisan composition of the final contest (Fisk, 2020; Patterson, 2020). On the other hand, newer work suggests that same-party general elections can also increase meaningful competition in heavily one-party districts relative to the old system, where the real contest effectively ended in the partisan primary (Sinclair, 2025).
So the honest scholarly position is this: A nonpartisan primary may improve competition and reduce partisan nomination gaming, but it also requires accepting some downstream participation tradeoffs in certain races.
That is still a trade worth serious consideration in Illinois, especially if the goal is to reduce nomination manipulation at the front end.
5. It treats voters equally in the first stage of candidate selection
Every voter receives the same ballot.
No one is forced into the artificial ritual of asking, “Which party ballot do you want today?”
In a state like Illinois, where voters can choose a party ballot on primary day, the current system effectively requires voters to enter a party lane before they can participate in nomination. A nonpartisan all candidate primary eliminates that asymmetry and treats every voter as an equal participant in the first stage of candidate selection (Illinois State Board of Elections, n.d.; McGhee & Shor, 2017).
That is not a trivial administrative difference. It is a cleaner democratic principle.
Why a Top Four Variant May Be Better Than Top Two
If Illinois were to adopt this reform, policymakers should seriously consider a top four model rather than stopping at top two.
A top two system is a substantial improvement over the current structure because it eliminates separate partisan nomination ballots. But a top four system may better preserve voter choice in a large and politically diverse state. It reduces the risk that a crowded field prematurely narrows the general election to only two candidates who may not fully reflect the state’s ideological or regional diversity.
A top four model also creates the possibility, if Illinois ever chose to pursue it, of later pairing that system with ranked choice voting in the general election, though that is a separate reform question.
The core point remains the same.
Whether top two or top four, the first principle should be identical: One ballot, one electorate, one transparent first round.
Conclusion
Illinois’s current primary system does not merely sort voters by party. It also permits strategic crossover selection by allowing voters to choose a party ballot at the point of voting and potentially influence the opposing party’s nominee. Whether or not such behavior determines every election, the institutional vulnerability is real, and the suspicion it creates is corrosive.
A nonpartisan all candidate primary would not solve every problem in Illinois politics, and the research does not justify utopian promises about immediate depolarization. But it would solve one very real problem: it would eliminate separate party nomination ballots and therefore eliminate the most obvious form of primary raiding and tactical sabotage.
It would also require candidates to appeal to a broader electorate from the beginning, which is a healthier democratic starting point than asking voters to strategically game two siloed partisan contests.
If Illinois wants less nomination manipulation, more transparent competition, and a fairer first stage of candidate selection, the case for a nonpartisan all candidate primary is strong.
Reference List
Ahler, D. J., Citrin, J., & Lenz, G. S. (2016). Do open primaries improve representation? An experimental test of California’s 2012 top two primary. Legislative Studies Quarterly, 41(2), 237–268. https://www.jstor.org/stable/43862566
Chen, K. P., & Yang, D. Y. (2002). Strategic voting in open primaries. Public Choice, 112(1/2), 1–30. https://www.jstor.org/stable/30026283
Fisk, C. A. (2020). No Republican, No Vote: Undervoting and Consequences of the Top-Two Primary System. State Politics & Policy Quarterly,, 20(3), 292–312. https://doi.org/10.1177/1532440019893688
Illinois General Assembly. (n.d.). 10 ILCS 5/7-1 et seq., Election Code, Article 7. https://www.ilga.gov/legislation/ilcs/details?ActID=170&ChapterID=3
Illinois State Board of Elections. (n.d.). Voting instructions and assistance. https://www.elections.il.gov/ElectionOperations/VotingInstructions.aspx
Masket, S. E. (2019). What is, and isn’t, causing polarization in modern state legislatures. PS: Political Science & Politics, 52(2), 343–346. https://www.cambridge.org/core/journals/ps-political-science-and-politics/article/what-is-and-isnt-causing-polarization-in-modern-state-legislatures/552C22D3FD93A16BB79602F8E4E0477C
McGhee, E., & Shor, B. (2017). Has the top two primary elected more moderates? Has the Top Two Primary Elected More Moderates? Perspectives on Politics, 15(4), 1053–1066. https://www.cambridge.org/core/journals/perspectives-on-politics/article/has-the-top-two-primary-elected-more-moderates/1F65856812342373F4A51B233E9BD593
Patterson, S., Jr. (2020). Estimating the unintended participation penalty under top two primaries with a discontinuity design. Electoral Studies, 68, Article 102231. https://doi.org/10.1016/j.electstud.2020.102231
Ranney, A. (1972). Turnout and representation in presidential primary elections. American Political Science Review, 66(1), 21–37. https://www.cambridge.org/core/journals/american-political-science-review/article/abs/turnout-and-representation-in-presidential-primary-elections/EF9C684DB806877B928D4AC5D3808388
Sinclair, J. A. (2025). Participation and competition in top two elections: Tradeoffs in election reform. State Politics & Policy Quarterly. Advance online publication. https://www.cambridge.org/core/journals/state-politics-and-policy-quarterly/article/participation-and-competition-in-toptwo-elections-tradeoffs-in-election-reform/C853759B1B596B91619DBE301B78D3DF
Woon, J. (2018). Primaries and candidate polarization: Behavioral theory and experimental evidence. American Political Science Review, 112(4), 826–843. https://doi.org/10.1017/S0003055418000515
