Make-or-break elections for Merkel coalition partner

According to the latest polls, the Liberal Free Democratic Party will score five percent, which is the minimum threshold to enter the Landestag, while McAllister's Christian Democrats are in the lead at 41 percent. The Social Democrats and Greens, currently in opposition and planning to rule together, would get 33 and 13 percent of the vote, meaning that both camps are neck-in-neck at 46 percent.

The Sunday elections are crucial for the political survival of Liberal leader and economy minister Philipp Roesler. Less than two years into the job, voters and fellow politicians are disappointed with his leadership style, seen as too weak and uncharismatic.

"Roesler is a nice guy, but people see him as a lightweight, they don't take him seriously. And that is deadly for a party chief. If they fail to make it into the Saxonian parliament on Sunday, Roesler will step down," says Oskar Niedermayer, a political scientist from the Berlin Free University.

At national level, all good things are attributed to Merkel and everything that goes wrong is "the Liberals' fault," Niedermayer told foreign journalists on Tuesday.

Merkel has the image of "mother of the nation", with voters approving of the way she is managing the euro-crisis while defending German interests, the academic noted. Her protegee McAllister - a German whose father was a Scottish soldier - meanwhile portrays himself as "regional father" of Lower Saxony, a term Merkel also used when going there to campaign for him.

McAllister's popularity and hands-on style spells out a future in national politics. Were he unable to remake the coalition in Lower Saxony, "it will be interesting to see how long before he switches to Berlin," Niedermayer says.

The Sunday elections will also be important for smaller parties like the Pirate Party and the leftist Linke. If they don't make it into the regional parliament, as polls currently indicate, Niedermayer predicts a negative impact on their campaign at federal level.

"There will be psychological effects: The ones winning will have energy and enthusiasm in the campaign for autumn, the ones having to stomach a massive loss will be in shock and could enter a negative spiral where their own campaigners don't feel motivated and nor do their voters," the scientist estimates.

As for Merkel's Social-Democratic challenger Peer Steinbrueck, his popularity has plummeted to 18 percent after a series of gaffes at the outset of his campaign. His party advisers are now trying to focus attention on issues and less on his person, as people vote for parties not candidates. But Steinbrueck's popularity problem are also weighing in on the party - estimated to score 23 percent, while Merkel's Christian Democrats are at 43 percent.

"Independent of the person of Steinbrueck, any candidate would have it very hard with Merkel. People form their image of politicians based on their credibility, competence, leadership and charisma. He should be better than Merkel at least in one area, but this is not the case," Niedermayer said.