The sun rises daily over official Washington, and the political consensus here changes just about as frequently. A few weeks ago the overpowering consensus was that big tax cuts were essential to economic well-being. Today's consensus is that taxes must be increased.

Thus the Treasury Department has started showing Republicans on Capitol Hill a rough draft of its new tax increase plan--a proposal to get back $22 billion of the $288 billion the Treasury will lose through 1984 from the big tax cut that passed two months ago. The draft sets forth a generally vague blueprint of the legislation sought, but congressional aides say one point comes through clearly: the losers will be big corporations.

Most of the legislative changes Treasury wants will hit corporate tax returns. These items include accounting rule changes that reduce a corporation's opportunity to defer until next year the tax bite on this year's earnings and elimination of a big tax exemption for insurance companies. The blueprint also cuts tax breaks for "industrial development" bonds, a change that would increase corporate borrowing costs.

Officially, by the way, the new package is not a "tax increase." Treasury officials call it their "tax enhancement" proposal.