The thank you to Trump was Handel's most public show of support of the man who wasn't embraced by many voters in the well-educated suburban Atlanta district in November and who she handled delicately throughout a primary and runoff election to fill the congressional seat vacated by Tom Price to take a spot in Trump's cabinet.
Trump also gloated about the win.
Handel defeated Democrat Jon Ossoff by more than four percentage points and Ossoff failed to reach the 48% mark that he topped in the initial round of voting. Super PACs and the National Republican Congressional Committee contributed a combined $18.2 million to defend the seat once occupied by former Speaker of the House Newt Gingrich and former Georgia Sen. The emperor's political health is failing, but they need to keep him alive, at least through 2018.
Karen Handel: Yes, of course she won, so she's a victor.
Trump also took to Twitter to praise Handel's win and celebrate Democrats' shutout in special elections.
"I don't want to offend anyone here, but if the Democrats want to start winning..." Democrats just lost their fourth special election in a row.
Trump's victory lap will be seen as a strong pushback.
"This was a pretty good fight. exciting to be a part of", Porter said of the Ossoff race. Since his upset win over Hillary Clinton, the former host of "The Apprentice" has only increased his opposition to the media, routinely labeling any reports he doesn't agree with as "fake news".
"The fact that all these races were close should have any member of the GOP who won by less than 15 points absolutely terrified", he said.
The election outcome will not alter the balance of power in Washington, where Republicans control both chambers of Congress. A neighboring district GOP chairman had said he believed the shooting could inspire GOP voters to come out to combat "left-wing extremism". She noted last week's shooting of Republican House Majority Whip Steve Scalise of Louisiana and said politics has become too embittered. A third of Americans say his approach to the issue has made their opinion of him worse, and his handling of that matter gets lower marks than any of his others, like the economy or terrorism, for which he rates higher.
Unaffiliated voters make up the largest percentage of the electorate in the Midwest state that backed Trump in 2016, after lifting Democrat Barack Obama to the White House in party caucuses and two straight elections. But veteran Republican operatives also warn against overreading the lessons of one special election. The previous three general elections were decided by an average of 14 points, and Trump won the district by 21 points.
Iowa independents who helped Donald Trump win the presidency see last year's tough-talking candidate as a thin-skinned chief executive and wish he'd show more grace.
Unprecedented sums of money has poured into the candidates campaigns.
Volunteers like Seger boosted Ossoff's campaign. And, at the end of the day, most of it will be wrong.
Handel, 55, will become the first Republican woman to represent Georgia in the US House of Representatives, according to state party officials.
Trump's foreign policy is as "winning" as his domestic policy, with the Syria crisis as his latest failure.
Handel's party has held the seat since 1979 and the Democratic Party is putting up a huge expensive fight to put a Democrat in the seat.
That followed another recent Democratic disappointment in Montana, where the Republican candidate won even after last-minute assault charges, and an earlier loss for the Democrats in Kansas.