WASHINGTON - Frustrated Democrats pondered the party's future and questioned its campaign messaging on Wednesday after a demoralizing defeat in a Georgia congressional race widely seen as a referendum on President Donald Trump's young administration.In the most expensive congressional election in US history, Republican Karen Handel, a former Georgia secretary of state, defeated political newcomer Democrat Jon Ossoff by 4 percentage points on Tuesday in a suburban Atlanta district that Republicans have held since the 1970s.The special election, to fill the seat vacated by Tom Price after Trump appointed him health and human services secretary, did not change the balance of power in Washington where Republicans control the White House and both chambers of Congress.But it was a demoralizing blow to Democrats hoping Georgia would be a breakthrough for a party trying to harvest electoral victories from the grassroots anti-Trump activism seen in marches on Washington and boisterous crowds at town hall meetings around the country. The district was seen as within reach to Democrats because Trump won there last November by only 1 percentage point.Democrats also lost a special election in South Carolina on Tuesday in a race Republicans were widely expected to win. Democrats lost two other contested special elections earlier this year for Republican-held seats in conservative Kansas and Montana. That makes the party 0-for-4 in this year's races for Republican-held congressional seats."Ossoff race better be a wake up call for Democrats - business as usual isn't working," tweeted Representative Seth Moulton of Massachusetts. "We need a genuinely new message, a serious jobs plan that reaches all Americans, and a bigger tent."Several prominent Democrats said the party needed to rethink its approach heading into next year's congressional elections, when Democrats need to pick up 24 seats to regain control of the House of Representatives.Senator Chris Murphy of Connecticut told MSNBC that Democrats needed to focus on economic growth and "get back to being a big tent party."'PARTY NEEDS NEW LEADERSHIP'The outcome also raised questions about the future of House Democratic leader Nancy Pelosi. Republican groups spent millions on television ads linking Ossoff to Pelosi, portraying him as a captive of the party's liberal wing despite Ossoff's efforts to present a more moderate image.In South Carolina, Charleston attorney and Democratic political newcomer Joe Cunningham said on Wednesday he would seek the House seat now held by Republican Mark Sanford, but that if elected he would not back Pelosi as the Democratic leader."The Democratic Party needs new leadership now," Cunningham tweeted.The road to a Democratic House majority runs through dozens of districts similar to the affluent, well-educated northern suburbs of Atlanta where Ossoff was defeated, and the outcome there is likely to reassure Republicans already nervous about their chances of holding control under Trump next year.The win in Georgia also could strengthen the political will of Republicans in Congress evaluating their next steps on a tax package and what opinion polls show is a deeply unpopular replacement of President Barack Obama's signature healthcare law.Trump was quick to celebrate the Georgia win and accused Democrats of standing in the way of a legislative agenda bogged down by infighting and investigations into whether his campaign colluded with Russia in last year's presidential election.At a rally in Cedar Rapids, Iowa, on Wednesday night, Trump said: "If Karen Handel had lost, they would have blamed it on me.""And don't forget, this happened in Montana, in Kansas," he added. "They don't get it. They haven't figured it out yet. You know they're still trying to figure where all those voters came from," he said of Democrats.Despite the string of losses in special elections, some Democrats said there were reasons to be encouraged. In all four states, Democrats bolstered their historical performance in districts they lost by double-digit margins last year.The unpopularity of Trump and the Republican healthcare bill - along with the historic trend that the party holding the White House loses seats in midterm elections - gives Democrats hope for capturing the House in 2018.Democrats have a target-rich environment next year, starting with 23 Republican-held districts where Democratic presidential candidate Hillary Clinton won a majority of the vote.