LONDON — Is the honeymoon over for Britain's unlikely political marriage?
Prime Minister David Cameron's coalition government, forged between his Conservatives and the left-leaning Liberal Democrats is showing the first signs of strain, less than two months after taking office following an inconclusive national election.
Two Liberal Democrat lawmakers voted against a key plank of the coalition's austerity budget, which will deliver tax hikes, sweeping cuts to welfare and the toughest reductions in public spending in decades.
Britain's Treasury chief George Osborne, a Conservative legislator, crafted the package announced last week to accelerate the country's attempts to reduce its massive national deficit.
Lawmakers on Monday endorsed a plan to raise value-added tax, a levy on goods and services, by 346 votes to 270, but two Liberal Democrat legislators rebelled – siding with the opposition Labour Party.
With a recent opinion poll showing that the Liberal Democrats, led by Deputy Prime Minister Nick Clegg, have rapidly lost support since teaming up with Cameron, some analysts question if Britain's coalition can hold.
"The first few weeks was the easy bit," said Steven Fielding, director of the Center for British Politics at Nottingham University. "It was always going to get harder."
Cameron and Clegg – who have carved a seemingly close personal working relationship – crafted a policy program for the country's first coalition government since World War II that required compromise on both sides.
Britain's May election saw no single party win an outright majority, but Cameron's group claim the most House of Commons seats.
The Liberal Democrats accepted their partner's plan to aggressively cut Britain's national debt – which in May rose above 900 billion pounds ($1.33 trillion). Its deficit stands at over 10 percent of gross domestic product.
In return, Cameron's party backed the Liberal Democrat's proposals to bolster civil liberties and put their hopes of overhauling Britain's voting system to a public referendum.
But analysts say the scale of cuts laid out in the budget has left some Liberal Democrat legislators reeling.
Mike Hancock and Bob Russell, both lawmakers with Clegg's party, voted against the proposal to raise value-added tax from 17.5 percent to 20 percent, worrying about its impact on the country's poorest families.
Chris Nicholson, director of Liberal Democrat-aligned think tank Center Forum, said economic policy and voting system reform are the likeliest sources of tension for the coalition.
Nicholson, formerly a Liberal Democrat council leader in south London, said some in Clegg's party are likely to balk when details of planned 25 percent cuts to budgets at most government departments are announced later this year.
"It's once you actually see what that means that people might start feeling a bit more unhappy," said Nicholson.
Fielding also identified the upcoming spending cuts as a hurdle. "When the cuts start hitting, that's going to be the second test," he said.
A new ComRes opinion poll published Tuesday showed support for Clegg's party has fallen since it joined in government with Cameron's Conservatives. The Liberal Democrats enjoyed an initial surge during the British election on the back of Clegg's accomplished television debate performances – but fell back sharply, and the party ended up losing rather than gaining seats.
The poll showed the Liberal Democrats with 18 percent support, down five points from a poll published June 20. The Conservatives had 40 percent and Labour 31 percent. ComRes interviewed 1,003 by telephone on June 25-27, no margin of error was given but in samples of a similar size is plus or minus three percent.
At the start of the election campaign, Clegg's party polled as high as 32 percent.
Clegg hopes changes aimed at bringing Britain's voting system closer to European-style proportional representation would increase the number of House of Commons seats his Liberal Democrats hold, and make coalition government more common in Britain. But no date has so far been set for the promised referendum, and some suspect Cameron hopes to leave his junior partners waiting as long as possible.
If the referendum on switching to a proportional system was lost, "then you would have many more Liberal Democrats asking if the coalition was worth it," Nicholson said.
"When the referendum will be held is of vital importance. The longer it is put off the Conservatives will have the Liberal Democrats locked in," Fielding said.
Cameron's Conservative Party has already confirmed it will campaign against any changes to the voting system, while Clegg's group will urge the public to vote in favor.