Germany's next election is expected sometime next year.
Despite facing some backlash over her open-door migrant policy, which has seen roughly 1 million migrants mostly from Middle Eastern war zones flock to the country, Merkel is seen as a bedrock of liberalism amid the shock of Britain's Brexit vote and outsider Donald Trump's election victory in the US.
Merkel represents "stability and reliability in turbulent times because she holds society together and stands up to over-simplification" by populists, CDU deputy leader Julia Kloeckner told Germany’s Welt am Sonntag newspaper, The Independent reported.
This new need for stability could help Merkel at the polls despite the ground her party has lost to the anti-immigrant Alternative for Germany (AFD) party in regional elections this year.
The AFD is expected to win seats in the national parliament next year, making coalition building tricky.
"We will have to deal with attacks from all sides," Merkel said at the CDU's Berlin headquarters Sunday, Politico reported.
Polls showed the day of the announcement that 55% of Germans would welcome a fourth term for the current leader, with 39% opposed.
"I thought about this for an endlessly long time. The decision (to run) for a fourth term is — after 11 years in office — anything but trivial," Merkel said at a news conference after a meeting of senior CDU members, Reuters reported.
Merkel was described as "last resistance fighter against newly elected American President Trump” by Willy Wimmer, former Parliamentary State Secretary in the German Defense Ministry, during US President Barack Obama’s visit to Berlin last week. Obama described Merkel as "an outstanding partner" and one of the US's most important allies. His trip was largely viewed as an effort to calm European colleagues ahead of the new administration.
During her tenure, Merkel has faced the euro zone debt crisis, the Ukraine crisis, Brexit and now Trump.
The CDU shares power with the Social Democrats (SPD), who have not announced whether they will run a candidate against her. Ralf Stegner, an SPD deputy leader, said it would be a mistake to underestimate Merkel but that the "myth of invincibility" was no more, Reuters reports.
There are no limits to the number of terms a chancellor can serve in Germany. If Merkel is reelected, she could match Helmut Kohl’s record 16 years in office.