In less than two weeks, we’ve watched the Dutch election transformed from a two-party race into a three-way tie, as the Dutch Labour Party leader Diederik Samsom has burst into a starring role on the Dutch political stage.

Samsom’s party, the social democratic Partij van de Arbeid (PvdA, the Labour Party), now either leads or is essentially tied with the two prior leading parties in advance of the September 12 elections for the Tweede Kamer, the lower house of the Dutch parliament.

Those two parties are the center-right, free-market liberal Volkspartij voor Vrijheid en Democratie (VVD, the People’s Party for Freedom and Democracy), led by current prime minister Mark Rutte, and the stridently leftist, anti-austerity Socialistische Partij (SP, the Socialist Party) led by Emile Roemer.

In the latest Ipsos Nederland poll and projection, Rutte’s VVD would win 34 seats, Roemer’s Socialists would win 27 seats and Samsom’s Labour would win 26 seats.  Three other smaller parties win a significant share of the vote: the anti-Muslim (and now increasingly anti-Europe) Partij voor de Vrijheid (PVV, the Party for Freedom), led by Geert Wilders, would win just 20 seats, the progressive Democraten 66 (Democrats 66) would win 14 seats, and the center-right Christen-Democratisch Appèl (CDA, Christian Democratic Appeal) would win just 13 seats.  TNS Nipo and Maurice du Fond polls show an even more ascendant Labour result.

Rutte’s VVD emerged with the most seats in the prior 2010 election, and he formed a minority government with the CDA, with outside support coming from Wilder’s PVV.  The current government fell in April, when Wilders refused to support Rutte’s budget package, which aimed to cut the 2013 Dutch budget to within 3% of GDP.

Labour, then headed by former Amsterdam mayor Job Cohen, finished with one fewer seat than the VVD in 2010, and is currently the main opposition party in the Tweede Kamer, but it had consistently lost support ever since — until now.  Cohen stepped down earlier this year, and Samsom, a more leftist Labour leader, replaced him in March.

So the latest poll capture the recent resounding resurgence for Labour, but also indicates that the Socialists and the Democrats 66 would still improve on their 2010 election totals, indicating that the Dutch parliament would be a much more anti-austerity parliament — a Labour-Socialist coalition is a possibility, as is a so-called ‘purple coalition’ between Labour and the VVD.  Labour last governed the Netherlands from 1994 to 2002 under prime minister Wim Kok, when the VVD and Labour joined together under a so-called ‘purple coalition’ (alongside the Dutch Greens and the Democrats 66), and Labour and the CDA governed in coalitions in the 1980s.

Whew! But that doesn’t explain why Samsom has so drastically improved his party’s chances to the point where he is now a credible contender, with Rutte and Roemer, to become The Netherlands’s next prime minister.  Here are five reasons why: 

It’s the debates, stupid.  Samsom has emerged as the near-consensus winner of the handful of party leader debates in the past two weeks, and it’s obvious that his rise in the polls flows from that success — his demeanor as a potential prime minister and his sharpness have impressed voters.  It’s not unlike in 2010 during the UK general election, when Liberal Democratic Party leader Nick Clegg suddenly shot to the top of the polls, briefly besting both then-prime minister Gordon Brown’s Labour Party and David Cameron’s Conservative Party.

Dutch voters are clearly looking for an anti-austerity alternative.  The number of seats projected for Rutte’s VVD hasn’t changed significantly — they’ve been projected to win anywhere from 28 to 34 seats throughout the election.  That means there’s a significant portion of the Dutch electorate that supports Rutte, believes that budget discipline marks the best way forward for the Dutch economy, and is committed to giving Rutte a chance to see his approach through.

But his coalition partner, the CDA, is polling at historically low levels of support, and as noted, Wilders’s 180-degree turn on Rutte is the proximate cause of the election.  So austerity’s becoming a lonelier proposition in Dutch politics, and there are obviously many voters who don’t support the austerity approach who are shopping around for a softer approach.  It reminds me a bit of the first Greek election earlier this year — it’s now clear that Alexis Tsipras’s SYRIZA (the Coalition of the Radical Left — Συνασπισμός Ριζοσπαστικής Αριστεράς) emerged as the strongest anti-austerity voice in Greece, but there were several options for anti-austerity voters, ranging from SYRIZA to the Democratic Left (which is now a member of the pro-bailout coalition), an anti-austerity right-wing group, the Greek communists and the neo-fascist Golden Dawn, among others.

Dutch voters are having second thoughts about Emile Roemer.  Initially, anti-austerity voters seemed to park their votes with the Socialists — despite the fact that they have fallen back in polls, after leading for much of August, polls still indicate that the Socialists would tie or improve upon their best showing in Dutch electoral history (25 seats).  At first glance, Roemer’s approach — bringing the budget within 3% of GDP by 2015 — seemed  reasonable enough.  But Roemer, for all his gregarious man-of-the-people mien, doesn’t have exactly the reputation as the smartest potential prime minister, and he’s had some rough moments in the debates where didn’t seem quite up to the task.

As Labour leader, Samsom is more leftist than was Cohen, which has narrowed the space between Labour and the Socialists on policy.  But Labour has historically been a very moderate party in the European social democratic tradition, while the Socialists formed in the early 1970s as a Maoist (!) communist party, and that may also be giving voters pause about handing the government to Roemer.

Dutch voters still believe in Europe.  Roemer’s comments earlier in the campaign about Europe — he’s taken a relaxedly casual take on whether Greece should remain in the eurozone, and he also indicated that he would thumb his nose at paying any fines for violating the European Union’s budget rules– demonstrated a flippancy to the European Union and an attitude that Dutch voters may not find comforting.  It’s clear that Roemer as Dutch prime minister would be very poorly received in Berlin or in Brussels, and Samsom’s strong pro-Europe stance has allowed him to be sufficiently anti-austerity without being anti-Europe (for example, unlike Roemer, he would join with VVD in favor of bailouts for other eurozone members).

Furthermore, Wilders has tried to out-radical the Socialists all summer long by emphasizing the PVV’s opposition to Dutch participation in the eurozone (he’s even suggested that The Netherlands leave the European Union altogether), and Dutch voters aren’t buying it.  Dutch voters, whose country was one of the initial six members of the European Coal and Steel Community formed in 1951, are still sufficiently pro-Europe to blanche at anti-euro posturing, whether from Roemer or from Wilders.

Samsom is the newest kid on the block, and timing is everything in politics.  Wilders and Rutte are familiar faces on the Dutch political scene, and Roemer is by now largely familiar to Dutch voters.  But Samsom is a relative newcomer at this level of Dutch politics, having just taken over the leadership of the Labour Party in March.  A nuclear physicist by training, and a longtime environmentalist, Samsom is only now just getting his first real look from Dutch voters, after a summer dominated by Rutte, Roemer and Wilders.  He’s telegenic, and he’s been an energetic campaigner throughout the summer in every corner of the country.  It’s clear that Dutch voters increasingly like what they see.

With the election just five days away, Samsom is cresting at just the right time — Rutte and Roemer have not had, and don’t seem likely to have sufficient time, to make a sustained case against Samsom.  Timing is everything in politics, and if Samsom and Dutch Labour emerges as the largest party next Wednesday, it will have a lot to do with the perfect timing of Samsom’s rise.