Today the Christian Democrats (CDU) approved the coalition agreement in a move that inches Mrs Merkel closer to her fourth term as German Chancellor.
Mrs Merkel has drawn criticism from more conservative members of her party for her open door migration policy of 2015, as well as her approach to the Greek banking crisis.
But despite tensions within the centre-right group the party, desperate to stay in power, threw their support behind a coalition deal struck the the SPD.
However the more formidable hurdle to ending a five-month political impasse in Europe’s largest economy comes in six days.
On Sunday March 4, results of a binding postal vote by members of the centre-left SPD will be announced and they are far less certain.
Now Mrs Merkel faces the tricker task of finding the approval of the SPD themselves – who are much more likely to oppose the deal as members fear another term of propping up Mrs Merkel risk damaging their future prospects.
Speaking at the CDU party congress Mrs Merkel said: “The fact we’re voting on a coalition treaty today five months after the election shows that we’re dealing with a difficult situation that we’ve never faced before.”
She reassured delegates that the new German government would not take out any new debt, avoid tax increases, seek to renew the European Union, ensure fast internet is available everywhere in Germany by 2025, boost research spending, create 8,000 nursing jobs and take a “zero tolerance” policy on security.
The CDU went on to elect Annegret Kramp-Karrenbauer as the party’s new general secretary – putting another centrist politician in the mould of the Chancellor in a position of power.
Receiving the title Mrs Kramp-Karrenbauer said that in uncertain times “it is no longer enough to point to others and say he or she should take responsibility, which is why I am now taking responsibility and placing myself at the service of the party”.
The move will be met with derision from the right wing of the party, who fear being outflanked by the far-right Alternative For Deutschland (AFD) after the eurosceptic party’s success in the 2017 election.
Over the weekend Mrs Merkel was urged by her conservatives to stick to the party’s conservative roots.
Senior CDU official Daniel Guenther said: ”Sometimes the conservative element of the conservative bloc could be more prominent.”
Bavarian conservative Alexander Dobrindt added: “The conservative bloc must cover the spectrum from the centre to the democratic right.”
It comes as the German Chancellor vows to bring reform to the European Union, branding her coalition as a “new dawn for Europe”.
Earlier this week she called for the EU to “prepare for change” ahead of 2019, when Britain leaves the bloc and Jean-Claude Juncker is replaced as EU president.
The German Chancellor, a strong anchor of Brussels, also expressed her desire for greater integration between member states in dealing with the migrant crisis, economic issues and security.
She said: “We want to have a Europe capable of action that is in solidarity and has self-confidence.
“To achieve this we must be ready to strengthen Europe where a European solution is better than a purely nationalist one.”
She added: “We can only continue to thrive in the future if EU thrives as well.”
After 12 years as chancellor and almost 18 years in charge of her party, Mrs Merkel’s authority is waning.
Her efforts to forge a coalition with two other smaller parties collapsed in November. That forced her to woo the SPD, which had been a coalition partner in her 2013-2017 government but was reluctant to repeat the experience after seeing its own support fall to its lowest since World War Two.
If SPD members vote “no” in their ballot, the most likely outcome is a new election or possibly a minority government.
Experts say a snap election could result in further gains for the anti-immigration AfD, which entered parliament for the first time in September.