It's the economy...

So excited were MPs by the fun-filled package of new legislation laid before them yesterday, that debate in the Commons petered out almost a good 20 minutes early - and had been flagging long before, with the Chamber all but deserted.

Not a good sign for the government. This lack of enthusiasm doesn't bode well for the scheduled five days of debate.

But the truth is that legislation is very much a side issue for the coalition now; its fate rests on the economy, and the main economic measures it is taking don't require new laws.

The events carrying the heaviest political wattage in this new session of Parliament will be the Budget and autumn statement, and responses to events in the euro-zone. Parliament's role is limited; it will hear statements and question ministers, select committees will report, but MPs and peers will not have much direct traction on the big policy decisions.

This is not to mock the bills announced in the Queen's Speech. Its contents matter a great deal, to particular interest groups. The unpromisingly-titled Groceries Code Adjudicator Bill, for example, is very important to farmers who feel squeezed by the buyers from big supermarkets.

The Public Service Pensions Bill will affect the retirement plans of millions of public-sector workers - and their cost to the taxpayer. The Banking Reform Bill will have huge implications in the City. And what should the governance arrangements be for the National Crime Agency?

But the pudding lacks a theme. Business organisations are already querying the lack of growth-promoting measures (although a lot of key policies don't require legislation, or are implemented via a budget) and eyebrows have been raised at the non-appearance of a bill to implement the HS2 rail line from London to Birmingham, which would have offered industry an infrastructure mega-project. I'm not sure too much should be read into that - the bill on HS2 is a vast and detailed creature, listing all the land to be acquired for the new route, and requires ultra-careful drafting. It was never likely to be passed in time for the next election. Perhaps there's a lesson there about the cumbersome way Parliament and the planning system process major infrastructure projects, but that's a different issue.

Will we actually see the promised battle royal over Lords reform? The Lib Dems insist we will. The prime minister is carefully equivocal, and other Conservatives confidently predict any bill will swiftly run into the sands.

As I write the Leader of the Commons, Sir George Young, has just promised a second reading debate before the summer - but as I blogged earlier, the real battles will take place around the programme motion and the committee stage. The different briefings from different quarters suggest that the coalition's internal battle has not been resolved.

Some of the most interesting action will revolve around the draft bill on social care - a subject which will touch the lives of almost everybody in Britain and has vast cost implications and important knock-on effects for the operation of the NHS.

The draft bill will presumably be scrutinised by a joint committee of MPs and peers - and the choice of that committee, and especially its chairman, will be worth watching. It should be a pretty senior figure - perhaps an ex-Cabinet policy heavyweight like the Conservative Peter Lilley - and its members from other parties will need sufficient stature to persuade their colleagues to sign up to a structure which will have to outlast individual governments.