Dec. 7, 1952: Susan Margaret Collins was one of six children born to Patricia and Donald Collins in Caribou. Elected service runs deep in the Collins family. Both of her parents served as mayor of that town, her father was a Maine state senator and members of four generations of the Collins family have served in the Legislature.

1971: Collins, then a senior at Caribou High School, visits Washington, D.C., as part of the U.S. Senate Youth Program and meets U.S. Sen. Margaret Chase Smith of Maine, who was the first woman to serve in both chambers of Congress and who ran for president in 1964. Collins has long called Smith a personal idol.

June 1971: Collins graduates second in her high school class and matriculated at St. Lawrence University in Canton, N.Y. She graduated with a bachelor’s degree in government in 1975 and took a job with then-Republican U.S. Rep. William S. Cohen.

1987: Collins is appointed as commissioner of the Department of Professional and Financial Regulation by Republican Gov. John McKernan.

1992: Collins is appointed by Republican President George H.W. Bush as the New England regional director for the Small Business Administration but holds the position only briefly before the election of Democratic President Bill Clinton.

1993: Collins becomes deputy state treasurer for the commonwealth of Massachusetts under Republican Gov. William Weld.

Sept. 14, 1993: Collins jumps into the 1994 gubernatorial election by telling the media that she would form an exploratory committee, touting her “deep commitment to Maine.” She left her Massachusetts post at the beginning of October.

June 14, 1994: Collins wins an eight-way Republican primary and becomes the first Maine woman to ever receive a party nomination for governor.

Sept. 28, 1994: Collins, whose campaign has struggled to gain traction, is rocked when her brother is charged with possessing 1,000 pounds of marijuana in a $1 million sting operation. Maine’s U.S. attorney says Susan Collins had no knowledge of his actions and she says she “can’t be responsible” for them, but she suffers in the polls.

Nov. 8, 1994: Collins places third in the November 1994 general election behind Democrat Joseph Brennan and the winner, independent Angus King.

Dec. 16, 1994: Collins is named founding executive director of the Center for Family Business at Bangor’s Husson College.

Feb. 7, 1996: Collins re-enters politics, declaring a run to replace the retiring Cohen in the U.S. Senate at an event at Husson College.

June 11, 1996: Collins easily wins a three-way Republican primary over and John Hathaway and Robert Monks with 55 percent of votes. Democrats give their nomination to Joe Brennan, even after national Democrats leaked a poll saying the former governor and congressman was likely to lose to Collins.

Nov. 5, 1996: Collins beats Brennan in a dogfight, getting 49 percent of votes to his 44 percent after a campaign that drew then-President Bill Clinton to Bangor to stump for Brennan — and his own re-election — on the day before Election Day.

January 1997: Collins secures her first chairman’s post in the Senate when she’s picked to head the Permanent Subcommittee on Investigations.

Feb. 12, 1999: Collins and fellow Maine Republican Sen. Olympia Snowe vote against both articles of impeachment against Clinton, who was acquitted of charges of perjury and obstruction of justice.

Nov. 5, 2002: Collins wins her first re-election against future Democratic congresswoman Chellie Pingree with 58 percent of votes to Pingree’s 42 percent, winning in every county — including Pingree’s home county of Knox.

November 2002: After Republicans take back the Senate majority in the 2002 election, Collins is picked to chair the Senate committee overseeing homeland security.

June 2006: Collins co-chairs a Senate committee that looked into the federal government’s response to Hurricane Katrina. The committee’s report found more federal resources could have saved lives.

Nov. 4, 2008: Collins wins her third election to the U.S. Senate against Democrat Tom Allen, 62 percent to 39 percent.

Dec. 18, 2010: Collins and Connecticut Sen. Joe Lieberman strike a deal that leads to the repeal of “Don’t Ask, Don’t Tell,” a former military policy that banned openly gay men and women from serving. Collins and former Republican U.S. Sen. Olympia Snowe of Maine were among eight Senate Republicans who voted for repealing the rule.

Jan. 23, 2011: Collins co-authors the National Alzheimer’s Project Act, which established a strategic national plan for combatting Alzheimer’s disease. This was one of many initiatives to fight dementia that Collins has been involved with, including co-chairing the Congressional Alzheimer’s Task Force.

Nov. 4, 2014: Collins wins her fourth election to the U.S. Senate against Democrat Shenna Bellows, 68 percent to 32 percent.

August 12, 2012: Collins marries Thomas A. Daffron in a small ceremony in Caribou. Collins and Daffron met years before while working for Cohen.

January 2013: Collins receives the Distinguished Public Service Award, the highest public service honor to civilians by the U.S. Navy. She would later win the VFW Congressional Award in March of 2017.

June 25, 2014: Collins becomes the fourth Republican senator, at the time, to publicly support same-sex marriage. Her decision came after Maine had already legalized same-sex marriage and after Collins won an endorsement from the national Human Rights Campaign.

Jan. 5, 2015: Collins is chosen to chair the Senate Special Committee on Aging.

Nov. 24, 2015: Collins garners a 78 percent approval rating in a Morning Consult poll, which was the second highest in the country. Another Morning Consult poll in April 2017 found that her approval rating had sunk to 67 percent.

Dec. 16, 2015: Collins is named the nation’s most bipartisan sitting senator by the Lugar Center at the McCourt School of Public Policy at Georgetown University. The organization gave her the same title in 2017.

Aug. 8, 2016: Collins announced in a newspaper column that she would not support nor vote for Donald Trump for president because, among other things, of his “inability to admit error or apologize.” It was a relatively bold stand at a time when pressure on Republicans to back their party’s nominee was considerable.

Jan. 18, 2017: Collins and one other Republican senator announce their opposition to a measure that would have cut Medicaid funding for Planned Parenthood.

Feb. 1, 2017: Collins votes against Betsy DeVos as Trump’s nominee to lead the U.S. Department of Education. DeVos was confirmed anyway.

Feb. 17, 2017: Collins becomes the only Senate Republican to oppose Trump’s nomination of Scott Pruitt to lead the Environmental Protection Agency. Pruitt was confirmed anyway.

Sept. 11, 2017: Collins co-authors a bill with a Democratic senator to block Trump’s call to ban transgender people from serving in the U.S. armed forces. The provision was not ultimately included in the 2017 National Defense Authorization Act, which passed in the Senate in mid-September.

Sept. 25. 2017: Collins votes, for the second time, against Trump and Republicans’ efforts to repeal and replace the Obama-era Affordable Care Act. She was among three Senate Republicans who blocked the Senate’s passage of the bill.

Christopher Cousins

Christopher Cousins has worked as a journalist in Maine for more than 15 years and covered state government for numerous media organizations before joining the Bangor Daily News in 2009.