Is Pakistan returning to pre-Musharraf political patterns? Nawaz Sharif’s decision to break with the PPP and pull his party, PML-N, out of Pakistan’s governing coalition, certainly suggests so. The story of the last months reflects, however, more general dynamics associated with democratization in competitive authoritarian regimes, i.e., those characterized by elections in which opposition groups have some ability to challenge an autocratic regime. It also reflects the growing importance of international-patron client relations for US foreign policy.

As Marc Howard and Philip G. Roessler argue (PDF), one of the most important factors bringing about liberalization in such regime is the formation of a coalition among opposition parties. As long as opposition groups remain divided, incumbents in competitive authoritarian regimes continue to rule. But once the opposition cooperates, it has a shot at overcoming electoral manipulation, structural barriers set up by the regime, and other efforts to maintain the status quo. And yet, as we’ve seen in other countries–most recently Kenya–such coalitions usually prove quite fragile when the spoils of victory arrive.

In this case, the PML-N remained with the PPP as long Sharif’s needed its support to remove Musharraf from office (remember that Musharraf’s coup was directed against Sharif). The other major “policy achievement” of the coalition government? A law granting retroactive immunity to their members for past corrupt acts, and making it extremely difficult to prosecute sitting politicians for corruption. But now, with the Presidency up for grabs and a debate over whether to reinstate the judges removed by Musharraf, its back to politics as usual. As the BBC reports:

The PPP fears that if all the judges sacked by Mr Musharraf get their jobs back, they may invalidate an amnesty that paved the way for Mr Zardari and Ms Bhutto to return to the country last year.

That would leave Mr Zardari open to prosecution on long-standing corruption charges.

The BBC’s Charles Haviland in Islamabad says the PPP has other parties in coalition and the government will not fall. However, the PPP may find Mr Sharif to be an uncomfortably powerful figure to have in opposition at a time when the country lacks a sense of political direction.

Mr Zardari and Mr Sharif worked together to threaten Mr Musharraf with impeachment which led him to resign last week.

The two party leaders had also agreed to reduce the powers of the presidency in a country where the president has in the past dismissed democratically elected governments.

Mr Sharif says as long as the presidency remains a powerful post, a non-partisan candidate acceptable to everyone, rather than Mr Zardari, should have been agreed on.

Given that Pakistan has emerged as one of the key battlegrounds for the struggle against the Taleban and Al-Qaeda, and given continued US uncertainty about how engage with post-Musharraf Pakistan, all this bears close attention.

There’s also a larger story at work here.

Consider the sites of the most visible challenges for US foreign policy of the last few years: Afghanistan, Iraq, Pakistan, and Georgia. What do these countries have in common? They’re all, to greater or lesser degrees clients of the United States. In each of them, moreover, the convergence of domestic political dynamics and relations with the United States has arguably diminished US leverage over key policy decisions, with consequences that significantly impact–for the worse–the ability of the United States to pursue its grand-strategic objectives.