{
 "topic": "senate",
 "site": "electiondata.dev",
 "place": {
  "id": "us-ia",
  "name": "Iowa",
  "level": "us-state",
  "parent": "usa",
  "path": "us/ia",
  "slug": "ia",
  "state": "ia",
  "state_name": "Iowa",
  "state_id": "us-ia"
 },
 "question": "How did Iowa vote for the Senate?",
 "answer": {
  "verdict": "Chuck Grassley (Republican) won by 12.0 points",
  "value": 12,
  "unit": " pts",
  "digits": 1,
  "label": "Senate, 2022: winner's margin",
  "lines": [
   "Chuck Grassley (Republican) 55.4%, Michael Franken (Democrat) 43.3%, Under Votes (party not recorded) 1.1%",
   "1,230,416 votes for Senate candidates"
  ]
 },
 "as_of": "2022",
 "as_of_label": "2022",
 "charts": [
  {
   "id": "senate-margin",
   "title": "Every regular Senate election in Iowa since 1978",
   "description": "16 regular elections; Democrats were ahead in 5 and Republicans in 11.",
   "indicator": "Democratic candidate's share of Senate votes minus the Republican's, points (regular elections; special elections are in the table)",
   "subtitle": "Democratic share minus Republican share, in points. Above the line: the Democrat got more votes.",
   "x": {
    "kind": "year"
   },
   "y": {
    "digits": 1,
    "unit": " pts",
    "format": "party-margin"
   },
   "layers": [
    {
     "type": "bars",
     "name": "Margin",
     "base": 0,
     "points": [
      [
       1978,
       -3.218,
       "rep"
      ],
      [
       1980,
       -7.946,
       "rep"
      ],
      [
       1984,
       11.797,
       "dem"
      ],
      [
       1986,
       -32.461,
       "rep"
      ],
      [
       1990,
       9.056,
       "dem"
      ],
      [
       1992,
       -42.414,
       "rep"
      ],
      [
       1996,
       5.095,
       "dem"
      ],
      [
       1998,
       -37.919,
       "rep"
      ],
      [
       2002,
       10.399,
       "dem"
      ],
      [
       2004,
       -42.307,
       "rep"
      ],
      [
       2008,
       25.395,
       "dem"
      ],
      [
       2010,
       -31.05,
       "rep"
      ],
      [
       2014,
       -8.339,
       "rep"
      ],
      [
       2016,
       -24.435,
       "rep"
      ],
      [
       2020,
       -6.478,
       "rep"
      ],
      [
       2022,
       -12.042,
       "rep"
      ]
     ],
     "legend": [
      {
       "label": "Democrat ahead",
       "cls": "dem"
      },
      {
       "label": "Republican ahead",
       "cls": "rep"
      }
     ]
    }
   ]
  }
 ],
 "limits": [
  "Statewide totals say nothing about who voted or why.",
  "Candidates with a party's support under another name (Minnesota's DFL, New York's fusion lines) are counted with that party, as the MIT data's simplified party does; independents stay independents."
 ],
 "method": "Each candidate's votes are summed over every ballot line; blank, over- and under-votes are left out. The margin is the winner's share of the votes minus the runner-up's. A runoff, where held, is the result.",
 "sources": [
  {
   "name": "electiondata.dev senate-results, version 2026-10-25.247421eda6",
   "url": "https://electiondata.dev/",
   "license": "CC0 1.0"
  },
  {
   "name": "MIT Election Data and Science Lab, U.S. Senate statewide 1976-2024",
   "url": "https://doi.org/10.7910/DVN/PEJ5QU",
   "license": "CC0 1.0"
  }
 ],
 "check": {
  "races": [
   {
    "year": 1978,
    "special": false,
    "runoff": false,
    "total": 824576,
    "votes": {
     "Roger W. Jepsen": 421598,
     "Dick Clark": 395066,
     "Gerald Leo Baker": 4223,
     "Ben L. Olson": 3689
    }
   },
   {
    "year": 1980,
    "special": false,
    "runoff": false,
    "total": 1276986,
    "votes": {
     "Charles E. Grassley": 683014,
     "John Culver": 581545,
     "Garry De Young": 5858,
     "Robert V. Hengerer": 4233,
     "John Ingram Henderson": 2336
    }
   },
   {
    "year": 1984,
    "special": false,
    "runoff": false,
    "total": 1292700,
    "votes": {
     "Tom Harkin": 716883,
     "Roger W. Jepsen": 564381,
     "Garry De Young": 11014
    }
   },
   {
    "year": 1986,
    "special": false,
    "runoff": false,
    "total": 891762,
    "votes": {
     "Charles E. Grassley": 588880,
     "John O. Roehrick": 299406,
     "John Masters": 3370
    }
   },
   {
    "year": 1990,
    "special": false,
    "runoff": false,
    "total": 983933,
    "votes": {
     "Tom Harkin": 535975,
     "Thomas J. Tauke": 446869
    }
   },
   {
    "year": 1992,
    "special": false,
    "runoff": false,
    "total": 1292494,
    "votes": {
     "Chuck Grassley": 899761,
     "Jean Lloyd-jones": 351561,
     "Stuart Zimmerman": 16403,
     "Sue Atkinson": 6277,
     "Mel Boring": 5508,
     "Rosanne Freeburg": 4999,
     "Carl Eric Olsen": 3404,
     "Richard O'dell Hughes": 2918,
     "Cleve Andrew Pulley": 1370
    }
   },
   {
    "year": 1996,
    "special": false,
    "runoff": false,
    "total": 1224054,
    "votes": {
     "Tom Harkin": 634166,
     "Jim Lightfoot": 571807,
     "Sue Atkinson": 9768,
     "Fred Gratson": 4248,
     "Joe Sulentic": 1941,
     "Shirley E. Pena": 1844
    }
   },
   {
    "year": 1998,
    "special": false,
    "runoff": false,
    "total": 947907,
    "votes": {
     "Charles E. Grassley": 648480,
     "David Osterberg": 289049,
     "Susan Marcus": 7561,
     "Margaret Trowe": 2542
    }
   },
   {
    "year": 2002,
    "special": false,
    "runoff": false,
    "total": 1023075,
    "votes": {
     "Tom Harkin": 554278,
     "Greg Ganske": 447892,
     "Timothy A. Harthan": 11340,
     "Richard J. Moore": 8864
    }
   },
   {
    "year": 2004,
    "special": false,
    "runoff": false,
    "total": 1479228,
    "votes": {
     "Charles E. Grassley": 1038175,
     "Arthur Small": 412365,
     "Christy Ann Welty": 15218,
     "Daryl A. Northrop": 11121,
     "Edwin Fruit": 1874
    }
   },
   {
    "year": 2008,
    "special": false,
    "runoff": false,
    "total": 1502918,
    "votes": {
     "Tom Harkin": 941665,
     "Christopher Reed": 560006
    }
   },
   {
    "year": 2010,
    "special": false,
    "runoff": false,
    "total": 1116063,
    "votes": {
     "Chuck Grassley": 718215,
     "Roxanne Conlin": 371686,
     "John Heiderscheit": 25290
    }
   },
   {
    "year": 2014,
    "special": false,
    "runoff": false,
    "total": 1129700,
    "votes": {
     "Joni Ernst": 588575,
     "Bruce Braley": 494370,
     "Rick Stewart": 26815,
     "Douglas Butzier": 8232,
     "Bob Quast": 5873,
     "Ruth Smith": 4724
    }
   },
   {
    "year": 2016,
    "special": false,
    "runoff": false,
    "total": 1541036,
    "votes": {
     "Chuck Grassley": 926007,
     "Patty Judge": 549460,
     "Charles Aldrich": 41794,
     "Jim Hennager": 17649,
     "Michael Luick-thrams": 4441
    }
   },
   {
    "year": 2020,
    "special": false,
    "runoff": false,
    "total": 1700130,
    "votes": {
     "Joni Ernst": 864997,
     "Theresa Greenfield": 754859,
     "Rick Stewart": 36961,
     "Under Votes": 27438,
     "Suzanne Herzog": 13800,
     "Over Votes": 864
    }
   },
   {
    "year": 2022,
    "special": false,
    "runoff": false,
    "total": 1230416,
    "votes": {
     "Chuck Grassley": 681501,
     "Michael Franken": 533330,
     "Under Votes": 13448,
     "Over Votes": 322
    }
   }
  ],
  "dataset": "senate-results",
  "version": "2026-10-25.247421eda6"
 },
 "table": {
  "title": "Every Senate race since 1976",
  "columns": [
   "Race",
   "Winner",
   "Runner-up",
   "Margin",
   "Votes"
  ],
  "num": [
   3,
   4
  ],
  "rows": [
   [
    "2022",
    "Chuck Grassley (R) 55.4%",
    "Michael Franken (D) 43.3%",
    "12.0 pts",
    "1,230,416"
   ],
   [
    "2020",
    "Joni Ernst (R) 50.9%",
    "Theresa Greenfield (D) 44.4%",
    "6.5 pts",
    "1,700,130"
   ],
   [
    "2016",
    "Chuck Grassley (R) 60.1%",
    "Patty Judge (D) 35.7%",
    "24.4 pts",
    "1,541,036"
   ],
   [
    "2014",
    "Joni Ernst (R) 52.1%",
    "Bruce Braley (D) 43.8%",
    "8.3 pts",
    "1,129,700"
   ],
   [
    "2010",
    "Chuck Grassley (R) 64.4%",
    "Roxanne Conlin (D) 33.3%",
    "31.0 pts",
    "1,116,063"
   ],
   [
    "2008",
    "Tom Harkin (D) 62.7%",
    "Christopher Reed (R) 37.3%",
    "25.4 pts",
    "1,502,918"
   ],
   [
    "2004",
    "Charles E. Grassley (R) 70.2%",
    "Arthur Small (D) 27.9%",
    "42.3 pts",
    "1,479,228"
   ],
   [
    "2002",
    "Tom Harkin (D) 54.2%",
    "Greg Ganske (R) 43.8%",
    "10.4 pts",
    "1,023,075"
   ],
   [
    "1998",
    "Charles E. Grassley (R) 68.4%",
    "David Osterberg (D) 30.5%",
    "37.9 pts",
    "947,907"
   ],
   [
    "1996",
    "Tom Harkin (D) 51.8%",
    "Jim Lightfoot (R) 46.7%",
    "5.1 pts",
    "1,224,054"
   ],
   [
    "1992",
    "Chuck Grassley (R) 69.6%",
    "Jean Lloyd-jones (D) 27.2%",
    "42.4 pts",
    "1,292,494"
   ],
   [
    "1990",
    "Tom Harkin (D) 54.5%",
    "Thomas J. Tauke (R) 45.4%",
    "9.1 pts",
    "983,933"
   ],
   [
    "1986",
    "Charles E. Grassley (R) 66.0%",
    "John O. Roehrick (D) 33.6%",
    "32.5 pts",
    "891,762"
   ],
   [
    "1984",
    "Tom Harkin (D) 55.5%",
    "Roger W. Jepsen (R) 43.7%",
    "11.8 pts",
    "1,292,700"
   ],
   [
    "1980",
    "Charles E. Grassley (R) 53.5%",
    "John Culver (D) 45.5%",
    "7.9 pts",
    "1,276,986"
   ],
   [
    "1978",
    "Roger W. Jepsen (R) 51.1%",
    "Dick Clark (D) 47.9%",
    "3.2 pts",
    "824,576"
   ]
  ]
 },
 "api": {
  "now": "/data/places/us-ia/senate.json",
  "source": "https://api.electiondata.dev/v1/senate-results/download/senate-results.csv",
  "source_label": "Every Senate race, every state, from electiondata.dev (live, no key)"
 },
 "generated_at": "2026-10-26T20:05:12+00:00"
}