Is Illinois the most demographically representative state?

[RINO Tom]

We certainly used to be circa the late 1980s, when Chicagoland made up a smaller percentage of the state's population, Downstate Illinois was a bit more thriving and the state was more in line with the nation politically (we voted for Bush in 1988 by just a couple points less than the nation).  More specifically, my hometown of Peoria was long described as a perfect little microcosm WITHIN such a representative state!  While the phrase "Will it play in Peoria?" did originally refer to our musical/play scene being one of the best springboards to Broadway, it indeed came to refer to Peoria being a great sample size of the American market place for products.

From the Pew Religious Landscape Survey:

National

Evangelical  25%
Mainline Protestant  15%
Catholic  21%
Non-Christian  6%
None  23%

...

Illinois

Evangelical  20%
Mainline  16%
Catholic  28%
Non-Christian  6%
None  23%

It is worth noting that Pew categorizes the Mainline churches as the Seven Sisters plus other theologically moderate-to-liberal churches (e.g., the Reformed Church in America) that are part of ecumenical organizations, and then they just lump all conservative denominations into their "Evangelical" category.  This is problematic, as groups like the Lutheran Church-Missouri Synod are not "Evangelical" in any way, shape or form ... they're just conservative.  They practice infant baptism, have formal liturgy, place a high emphasis on the sacraments and church tradition, etc.  They are in no way "Born Again."  Thus, many denominations researchers (such as Joshua from the Ready to Harvest YouTube channel) prefer an additional category of "Confessional Protestant," which describes the more conservative denominations from the more historic/classical Protestant traditions.  

If you moved those groups out of the "Evangelical" category and left that category to refer more to what we think of as "Evangelical" like Baptists, Pentecostals, Non-Denominational, etc., Illinois' numbers would look like this:

16% MAINLINE PROTESTANT
3% United Methodist Church
2% Evangelical Lutheran Church in America
2% American Baptist Churches USA
1% Presbyterian Church (USA)
1% Episcopal Church
1% United Church of Christ
6% Other

15% EVANGELICAL PROTESTANT
2% Southern Baptist Convention
2% Independent Baptists
2% Christian Churches and Churches of Christ
1% Assemblies of God (Pentecostal)
5% Non-Denominational
3% Other

5% CONFESSIONAL PROTESTANT
3% Lutheran Church-Missouri Synod
1% Presbyterian Church in America and other Presbyterian denominations
1% Anglican, Methodist, Congregationalist, etc. confessional denominations

TL;DR

If you are speaking of what everyone would think of as "Mainline" and "Evangelical" denominations, there are more Mainline Protestants in Illinois.  The problem is lumping groups that are not Evangelical in with the Evangelical category for Pew.

[RINO Tom]

We certainly used to be circa the late 1980s, when Chicagoland made up a smaller percentage of the state's population, Downstate Illinois was a bit more thriving and the state was more in line with the nation politically (we voted for Bush in 1988 by just a couple points less than the nation).  More specifically, my hometown of Peoria was long described as a perfect little microcosm WITHIN such a representative state!  While the phrase "Will it play in Peoria?" did originally refer to our musical/play scene being one of the best springboards to Broadway, it indeed came to refer to Peoria being a great sample size of the American market place for products.

From the Pew Religious Landscape Survey:

National

Evangelical  25%
Mainline Protestant  15%
Catholic  21%
Non-Christian  6%
None  23%

...

Illinois

Evangelical  20%
Mainline  16%
Catholic  28%
Non-Christian  6%
None  23%

It is worth noting that Pew categorizes the Mainline churches as the Seven Sisters plus other theologically moderate-to-liberal churches (e.g., the Reformed Church in America) that are part of ecumenical organizations, and then they just lump all conservative denominations into their "Evangelical" category.  This is problematic, as groups like the Lutheran Church-Missouri Synod are not "Evangelical" in any way, shape or form ... they're just conservative.  They practice infant baptism, have formal liturgy, place a high emphasis on the sacraments and church tradition, etc.  They are in no way "Born Again."  Thus, many denominations researchers (such as Joshua from the Ready to Harvest YouTube channel) prefer an additional category of "Confessional Protestant," which describes the more conservative denominations from the more historic/classical Protestant traditions.  

If you moved those groups out of the "Evangelical" category and left that category to refer more to what we think of as "Evangelical" like Baptists, Pentecostals, Non-Denominational, etc., Illinois' numbers would look like this:

16% MAINLINE PROTESTANT
3% United Methodist Church
2% Evangelical Lutheran Church in America
2% American Baptist Churches USA
1% Presbyterian Church (USA)
1% Episcopal Church
1% United Church of Christ
6% Other

15% EVANGELICAL PROTESTANT
2% Southern Baptist Convention
2% Independent Baptists
2% Christian Churches and Churches of Christ
1% Assemblies of God (Pentecostal)
5% Non-Denominational
3% Other

5% CONFESSIONAL PROTESTANT
3% Lutheran Church-Missouri Synod
1% Presbyterian Church in America and other Presbyterian denominations
1% Anglican, Methodist, Congregationalist, etc. confessional denominations

TL;DR

If you are speaking of what everyone would think of as "Mainline" and "Evangelical" denominations, there are more Mainline Protestants in Illinois.  The problem is lumping groups that are not Evangelical in with the Evangelical category for Pew.

I think you're misunderstanding the definition of "Evangelical".  Certainly, many Evangelical churches are of the "low-church" variety, like Baptists, that believe in credobaptism and have a more symbolic view of sacraments.  But, that's not what defines Evangelical.  "Evangelical" means believing in the need to evangelize (due to believing that all non-Christians go to Hell).  Conservative denominations like the PCA, LCMS, ACNA, and Methodist offshoots believe that.  That's why they're classified as "Evangelical".

The Pew study specifically states in its methodology that it is using "Evangelical" and "born-again" as synonymous.  Even if we grant that confessional Protestant denominations like the LCMS have some significant emphasis on evangelism efforts (I would certainly dispute this), they are NOT "born again."  Lutheran, Presbyterian, Anglican, etc. theology specifically teaches AGAINST some type of second "born again" experience, believing that baptism is a sacrament and an act by God (not an act by men to show faith or something) ... it is fundamentally different from the more Baptist understanding of what makes someone a "Christian" - a necessary "born again" experience.

Even ignoring all of that, I will tell you as someone that was baptized LCMS Lutheran that zero people in that denomination would identify as "Evangelical," which is why other studies that use the methodology of first asking if someone is Protestant and then asking if they are "Evangelical" actually show that there are more Mainline Protestants ... because they do the opposite of Pew by defining "Evangelical" first and then lump everybody else into some "Mainline" category.  I believe both methods are very flawed and end up inflating the numbers for one group ... hence why I prefer the categorization method of adding another "Confessional Protestant" category.

I'll tell you right now that even with your conservative theology, you would feel more at home in an American Baptist Churches USA church than an LCMS Lutheran one.