BERLIN (AP) — Elections in two German states on Sunday pose a difficult test for Chancellor Angela Merkel's party, six months before a national vote that will determine who succeeds the country's longtime leader.

Voters are choosing new regional legislatures in Baden-Wuerttemberg, an economic powerhouse region in southwestern Germany, and neighboring Rhineland-Palatinate.

Those ballots kick off an electoral marathon this year, which features six state elections and culminates in the Sept. 26 vote for a new national parliament.

Polls point to weak results for Merkel's center-right Christian Democratic Union. Amid discontent over a sluggish start to Germany’s vaccination drive, and with coronavirus restrictions easing only gradually, Merkel’s Union bloc has been hit over the past two weeks by allegations that two lawmakers profited from deals to procure masks early in the coronavirus pandemic.

The CDU already faced a challenging task against two popular state governors from rival parties.

In Baden-Wuerttemberg, Germany's only Green party governor, Winfried Kretschmann, has become popular with centrist voters in 10 years running a region that is home to automakers Daimler and Porsche. The region was long dominated by the CDU until Kretschmann won power shortly after Japan's 2011 Fukushima reactor disaster, which accelerated the end of nuclear power in Germany.

Kretschmann, 72, a fatherly figure with a conservative image, features on Green election posters with the slogan “You know me.” That is a slogan that Merkel famously once used in a pre-election debate to underline her own largely ideology-free appeal.

In Baden-Wuerttemberg's last election in 2016, the Greens overtook the CDU to become the strongest party in the state. Polls suggest they can hope to widen their lead Sunday.

That would be a hopeful signal for the national election campaign, in which the traditionally left-leaning environmentalist party is expected to make its first bid for the chancellery. Merkel isn't seeking a fifth term after nearly 16 years in power.

About 7.7 million people are eligible to vote in Baden-Wuerttemberg and some 3.1 million in Rhineland-Palatinate. The center-left Social Democrats have led that region for 30 years — currently under governor Malu Dreyer, whose personal popularity has kept her party’s support above its dismal national ratings. Dreyer is the favorite this time, though in a close race.

It's an awkward moment for new CDU leader Armin Laschet to face his first major test since being elected in January. Laschet has sought to pre-empt any fallout, saying that state elections “always have their very own character” and the outcome won't affect the stability of his leadership. However, bad results may raise questions over his hopes of running to succeed Merkel in September.

Many people had already voted by mail, so it’s unclear how far the scandal — over lawmakers in the CDU and its Bavaria-only sister party, the Christian Social Union, allegedly enriching themselves through mask deals — will impact Sunday’s vote. Nikolas Loebel, a CDU lawmaker from Baden-Wuerttemberg, and the CSU’s Georg Nuesslein have both quit their parties and say they won’t run for parliament again.

The Union bloc of CDU and CSU benefited from Merkel’s perceived good management of the pandemic over the past year. It still leads national polls by a distance, but this year has started badly. Germany’s vaccination campaign has been significantly slower than those of Israel, Britain and the U.S.

Laschet says that he and Markus Soeder, the CSU leader and Bavarian governor who is the other serious contender to run for chancellor, will decide on the center-right candidate to succeed Merkel in April or May. Soeder has gained in stature during the pandemic.