One of the most astounding legislative and societal shifts I have seen in my lifetime has been how the American public and its legislators perceive issues surrounding people who are not strictly heterosexual. What I aim to do for this post and the next one is to organize important votes surrounding what we now call LGBT rights issues and ultimately explain what happened with this shift in opinion. For some of these votes early on I’m going to include ones surrounding AIDS, as this illness was in the 1980s largely perceived as mostly impacting homosexual men. Also included are efforts at prohibiting equal recognition through benefits of married and unmarried couples. The most striking shifts I’m seeing so far include on same-sex marriage and gays in the military. I also doubt that 20-25 years ago people were thinking that there would be a universal embrace of trans rights issues by the Democratic Party. Additionally, I’m seeing that some of the change is due to Democratic legislators who voted against LGBT measures losing reelection to Republicans or have since retired.
Senate
Votes
Mathias (R-Md.) Motion to Table Helms (R-N.C.) Amendment, Nullifying a D.C. Law Prohibiting AIDS Testing of Insurance Policy Applicants.
Rejected 41-53: R 15-34; D 26-19, 8/1/86.
Danforth (R-Mo.) Motion to Table Helms (R-N.C.) AIDS Testing Requirement for Immigrants and Marriage License Applicants.
Passed 63-32: D 39-8; R 24-24, 5/21/87.
Armstrong Amendment, Exempt Religious Institutions from Law Prohibiting Bias Against Gays and Lesbians in Washington D.C.
Passed 58-33: D 21-25; R 37-8, 7/11/88.
Weicker (R-Conn.) Motion to Table Helms (R-N.C.) Amendment
The Helms amendment blocked funding for the Department of Health and Human Services until a prohibition was issued against the promotion of alternative lifestyles.
Passed 47-46: D 35-11; R 12-35, 7/27/88.
Mitchell (D-Me.) Motion to Table Helms (R-N.C.) Amendment to the Americans With Disabilities Act, Permitted Transfer of Food-Handling Employees with Communicable Diseases to Equivalent Paying Positions.
Rejected 40-53: D 32-17; R 7-36, 6/6/90.
Kennedy (D-Mass.) Motion to Table Helms (R-N.C.) Amendment, Permitting Health Care Officials to Test Patients for AIDS Before Invasive Medical Procedures Except in Emergencies.
Rejected 44-55: D 35-19; R 8-36, 7/30/91.
Helms (R-N.C.) Amendment Excluding From Federal Employee Contribution Fund Charities That Withdraw Support for the Boy Scouts of America.
Rejected 49-49: D 17-36; R 32-12, 9/22/92.
Boxer (D-Calif.) Amendment, Overturn “Don’t Ask, Don’t Tell”.
Rejected 33-63: D 28-24; R 4-39, 9/9/93.
Helms Amendment, Prohibit Funds for Ryan White Act Being Used to Directly or Indirectly Promote Homosexuality or Intravenous Drug Use.
Adopted 54-45: R 40-13; D 14-32, 7/27/95.
Defense of Marriage Act
Passed 85-14: R 53-0; D 32-14, 9/10/96.
Prohibit Job Discrimination Based on Sexual Orientation
Rejected 49-50: R 8-45; D 41-5, 9/10/96.
Kennedy Hate Crimes Amendment, Adopted 57-42: R 13-41; D 44-1, 6/20/00.
Helms Amendment, Boy Scouts
Adopted 51-49: D 8-42; R 43-6; I 0-1, 6/14/01.
End Debate, Hate Crimes Based on Sexual Orientation
Rejected 54-43: D 49-1; R 4-42; I 1-0, 6/11/02.
Note: Senate Majority Leader Tom Daschle (D-S.D.) voted against as a parliamentary maneuver so he could potentially reintroduce it later in the session.
Smith (R-Ore.) Amendment, Add Hate Crimes Legislation That Includes Sexual Orientation.
Adopted 65-33: R 18-33; D 47-0, 6/15/04.
Federal Marriage Amendment Cloture
Rejected 48-50: R 45-6; D 3-43, 7/14/04.
Federal Marriage Amendment Cloture
Rejected 49-48: R 47-7; D 2-40; I 0-1, 6/7/06.
Kennedy Hate Crimes Amendment, Invoke Cloture.
Agreed 60-39: D 49-0; R 9-39; I 2-0, 9/27/07.
Invoke Cloture on Hate Crimes Bill for Sexual Orientation.
Passed 63-28: D 56-0; R 5-28; I 2-0, 7/16/09.
Don’t Ask, Don’t Tell Repeal Act of 2010
Passed 63-33: D 55-0; R 8-31; I 2-0, 12/18/10.
Toomey (R-Penn.) Amendment, Religious Freedom Protection in Non-Discrimination Requirement.
Rejected 43-55: D 2-50; R 41-3; I 0-2, 11/7/13.
House
Hate Crimes Statistics – Substitute “Homosexuality” or “Heterosexuality” for “Sexual Orientation” Under Reporting Categories
Passed 384-30: D 243-2; R 141-28, 5/18/88.
Dixon (D-Calif.) Motion, Weaken Senate Armstrong Amendment Regarding Religious Exemptions for Sexual Orientation Anti-Discrimination Law of D.C..
Rejected 134-201: R 11-124; D 122-77, 9/30/88.
Dannemeyer (R-Calif.) Amendment requiring reporting AIDS to the state public health office as a condition for AIDS Federal Policy funds.
Rejected 70-327: D 4-228; R 66-97, 10/22/88.
Natcher (D-Ky.) Motion, Kill Dannemeyer (R-Calif.) Amendment, Prohibiting Funds Appropriated for Education From Being Spent to Teach About Homosexuality or Bisexuality.
Passed 279-134: D 236-6; R 43-128, 8/2/89.
Dannemeyer (R-Calif.) Amendment, Exempt Religious Organizations from Anti-Discrimination Law Based on Sexual Orientation
Passed 262-154: D 109-133; R 153-20, 10/3/89.
Chapman (D-Tex.) Amendment, Permitting Transfer of Food-Handling Employees with Communicable Diseases to Equivalent Paying Positions.
Passed 199-187: D 78-154; R 121-32, 5/17/90.
DeLay (R-Tex.) Motion to Prohibit D.C. from Granting Same Benefits for Domestic Partnerships as Marriages.
Passed 235-173: D 90-156; R 145-16: I 0-1, 9/24/92.
Istook (R-Okla.) amendment, Prohibit Funds for Enforcing D.C. Domestic Partners Ordinance, Granting Unmarried Couples Same Benefits as Married.
Passed 251-177: D 94-162; R 157-14; I 0-1, 6/30/93.
Hunter (R-Calif.) Amendment, Require Defense Department to Ask Armed Forces Applicants on Sexual Orientation.
Rejected 144-287: D 29-224; R 115-61; I 0-1, 9/28/93.
Meehan (D-Mass.) Amendment, Strike Provisions Codifying a Ban on Homosexuals in the Military.
Rejected 169-264: D 157-101; R 11-163; I 0-1, 9/28/93.
Defense of Marriage Act
Passed 342-67: R 224-1; D 118-65; I 0-1, 7/12/96.
Conyers Hate Crime Legislation, Include Sexual Orientation Amendment to the National Defense Authorization Act.
Agreed to 232-192: R 41-175; D 190-16; I 1-1, 9/13/2000.
Weldon (R-Fla.) Amendment, Prohibit the Use of Local and Federal Funds to Extend Health Benefits to Unmarried Domestic Partners.
Failed 194-226: R 175-41, D 18-184; I 1-1, 9/25/01.
Marriage Protection Amendment
Rejected 227-186: R 191-27; D 36-158; I 0-1, 9/30/04.
Conyers Hate Crimes Amendment
Adopted 223-199: R 30-194; D 192-5; I 1-0, 9/14/05.
Marriage Protection Amendment
Rejected 236-187: R 202-27; D 34-159; I 0-1, 7/18/06.
Hate Crimes Bill for Sexual Orientation
Passed 249-175: D 231-17; R 18-158, 4/29/09.
Don’t Ask, Don’t Tell Repeal Act of 2010.
Passed 250-175: D 235-15; R 15-160, 12/15/10.
Huelskamp (R-Kan.) Amendment, Bar Use of Federal Funds to Train Military Chaplains to Implement “Don’t Ask, Don’t Tell” Repeal.
Passed 236-184: R 227-9; D 9-175, 7/8/11.
Equality Act
Passed 236-173: D 228-0; R 8-173, 5/17/19.
Equality Act
Passed 224-206: D 221-0; R 3-206, 2/25/21.
Mad Politics: The Bizarre, Fascinating, and Unknown of American Political History 
Great analysis as usual. It seems that people back then in general were more socially conservative than nowadays, which may explain why determinants for what constitutes a conservative or liberal prior to the 60s and 70s often seem to be based on economic and foreign policy issues. As for LGBT matters, another important thing to mention is the investigation by Kenneth Wherry and J. Lister Hill in 1950 of homosexuals in the State Department, which was part of the Lavender Scare.
Thanks again! In the course of my research for the follow-up post, I have found that the American public grew more liberal on most moral issues from 2001 to 2015, with the most dramatic shift being in same-sex marriage. And yes, I plan on giving the Lavender Scare some coverage with this next one.