Prime Cabinet Secretary Musalia Mudavadi and National Assembly Speaker Moses Wetang'ula's bid to lock down the Western vote for President William Ruto now faces a major test.
The development comes after Nairobi Senator Edwin Sifuna and Trans Nzoia Governor George Natembeya unveiled a strategy to ring-fence the vote-rich region.
Wetang'ula and Mudavadi are leading the President's re-election campaign in the region ahead of the 2027 General Election.
They have been traversing the region, urging residents to support the Kenya Kwanza administration.
That strategy is now facing its biggest political test.
Leaders allied to the Linda Mwananchi and Tawe movements have announced plans to form a new political party.
They also want to unite the Western vote behind Sifuna's presidential bid.
The team endorsed the Nairobi Senator as its preferred presidential candidate.
"The resolutions reached following a meeting at the home of Natembeya are that Luhya leaders allied to Linda Mwananchi will rally behind Sifuna ahead of the 2027 General Election," Vihiga Senator Godfrey Osotsi said.
The resolution followed a 10-hour meeting.
Kakamega Senator Boni Khalwale said the Sifuna wave would not only sweep away the political establishment in the region but also seal Ruto's political fate.
"Over the years, the country's politics has been along ethnic and regional lines. Sifuna finds himself in a very unique position. He enjoys both regional and ethnic support," Khalwale said.
"Sifuna also enjoys massive youth support across the country. Coupled with regional and ethnic support, he will be the person to beat. He will sweep everywhere," he added.
However, Ruto's presidential campaign deputy coordinator in the region, Ayub Savula, dismissed Sifuna as a "joker" who faces a tall order in turning the tables.
"In 2013, Mudavadi ran for President. What impact did he have? Zero. That is what will befall Sifuna. We have 29 MPs, four governors and four deputy governors. Sifuna has one governor and two MPs. How will he win?" he posed.
He said Ruto has campaign layers comprising local, regional and national leaders who will sink Sifuna's fortunes in the region.
Addressing journalists on Sunday, Natembeya declared that Western Kenya was entering a new political chapter.
"White smoke is beginning to billow from Western Kenya," he said.
"We have agreed to establish a political party that will carry the Linda Mwananchi agenda into the 2027 elections. Our goal is to unite Western Kenya politically while building a national movement capable of competing for power."
The movement will begin its campaigns with a rally in Trans Nzoia county on July 25.
Another rally, dubbed the "mother of all rallies", will be held in Bungoma the following day.
Natembeya said the Bungoma meeting would formally endorse Sifuna as the political leader of the Luhya community.
"The Bungoma meeting will crown Sifuna as the political leader of the Luhya nation before releasing him to embark on a nationwide presidential campaign," he said.
Osotsi said the political party that will carry the movement into the elections will be unveiled soon.
The endorsement is the strongest political backing Sifuna has received since talk of his presidential ambitions emerged.
Although the ODM secretary general has maintained his immediate focus is on strengthening the opposition, his allies have stepped up calls for him to contest the presidency.
The leaders announced a series of rallies across all 38 constituencies in the region aimed at encouraging voter registration and rallying support for their political agenda.
"We are going to launch vigorous grassroots campaigns in all 38 constituencies in Western Kenya to mobilise our people to register as voters and support our political agenda," Natembeya said.
The meeting brought together Osotsi, Bumula MP Jack Wamboka, Kabuchai MP Majimbo Kalasinga and several elected leaders.
The new political alliance raises the stakes for Mudavadi and Wetang'ula.
"Natembeya is the leader on political matters in the Western region. Those who fail to identify with him and Sifuna will face the verdict of the electorate," Kalasinga said.
The two leaders are expected to deliver Western votes for Ruto in 2027.
They have repeatedly urged the region to remain in government and support the President's second-term bid.
Western has become one of the country's key political battlegrounds.
The region commands more than two million votes.
Both Kenya Kwanza and the opposition view it as crucial to winning the next election.
Ruto has invested heavily in the region since taking office.
He appointed Mudavadi as Prime Cabinet Secretary and retained Wetang'ula as National Assembly Speaker.
The President has also launched several development projects and made frequent tours of the region.
The emergence of the Sifuna-Natembeya alliance threatens to upset those plans.
The alliance wants Western to rally behind one candidate instead of splitting its vote among several leaders.
If it succeeds, it could weaken the influence of Mudavadi and Wetang'ula.
It could also deny Ruto a significant share of votes from a region he considers central to his re-election strategy.
The timing is also significant.
Ruto is facing growing political resistance in several regions, including Mt Kenya.
Losing ground in Western would complicate his path to a second term and force Kenya Kwanza to fight harder in a region it had hoped to dominate.
The declaration builds on weeks of mobilisation under the Linda Mwananchi movement.
Sifuna has already announced plans for a major convention in Bungoma.
INSTANT ANALYSIS
The Sifuna-Natembeya alliance signals a new battle for Western Kenya, a region President William Ruto views as critical to his 2027 re-election bid.
By seeking to unite the Luhya vote behind one political vehicle, the alliance directly challenges the influence of Musalia Mudavadi and Moses Wetang'ula.
If it gains traction, Ruto could lose a key electoral cushion, forcing Kenya Kwanza to expend more political capital defending Western while battling a resurgent opposition elsewhere.