German Chancellor to chart 2017 election battle at party congress

When her centre-right Christian Democratic Union (CDU) holds its annual two-day congress from Tuesday, she will seek to rally members behind her bid for a fourth term as Germany's leader.

Her opponents will seek to capitalise on resentment over her liberal refugee policy that brought one million asylum seekers to Europe's biggest economy over the past two years.

Here is an outline of what the CDU congress in the western city of Essen is about.

What is expected to happen?

The event opens Tuesday with a speech by Merkel, who has led the CDU for 16 years after ousting long-time leader Helmut Kohl.

The 62-year-old is due to give a rundown on what she has achieved since their last congress, especially on the hot-button issue of reducing the mass influx of refugees and migrants.

Crucially, the party faithful will be keen to hear how she expects to take the party forward into the coming election year, which will pit the CDU against its current coalition partner the Social Democrats and several smaller parties.

Will anyone challenge her?

There is no question Merkel will win a new two-year mandate to helm the CDU, but her score, and the length of the standing ovation, will be closely scrutinised for any signs of dissent.

At the last vote in 2014, she scored a North Korean-style 96.7 percent, just below her record high of 97.9 percent from 2012.

Several potential successors have been floated, but no one has caught the wider public's imagination -- among them Interior Minister Thomas de Maiziere and Defence Minister Ursula von der Leyen.

Most German voters still feel comfortable with "Mutti" (Mummy) -- a survey found 64 percent welcomed her new candidacy against 33 percent who did not.

Political analyst Hajo Funke of Berlin's Free University said Merkel had made "the correct decision, for both the party and for Germany's stability".

Despite some grumbling from their Bavarian CSU allies, angered by the migrant influx, the conservative CDU rank-and-file "know who generates power for their party," Funke said.

What else will they discuss?

While CDU members approve of Merkel's fourth term bid as chancellor, not all are on board with her policies.

Merkel will be called to account for the party's poor showing in five consecutive state elections this year in a voter backlash driven by the migrant crisis.

Linked to that are questions on how the party can counter the leaching away of support to the right-wing populist and anti-Islam Alternative for Germany (AfD), which is polling around 12 percent.

To address some of the concerns, party chiefs will propose banning the full-face Muslim veil and cracking down on marriages involving minors.

Some may seek a tougher stance on immigration. CDU deputy chairman Thomas Strobl last week set out a demand to streamline the extradition of rejected asylum seekers.

But it remains unclear if his proposal will be put to the congress, or whether party leaders will try to quash unwelcomed suggestions through backroom compromises.

What's next for Merkel?

With the party congress, the CDU kicks off a long election campaign in which Merkel will seek to capture the middle ground.

CDU general secretary Peter Tauber said "all the questions that currently preoccupy the population also preoccupy CDU members".

Merkel's party next year faces three state elections, with momentum steadily building to the last regional poll in May in Germany's most populous state, North Rhine-Westphalia.

The new year promises to throw up a host of new international challenges. It will see Trump move into the White House and Britain start its EU exit negotiations.

Merkel will also watch carefully the hotly contested French presidential election and its impact on key EU issues, including migration and attitude towards Russia.