NEW YORK (CNN/Money) - If the devil is in the details, we could be in for a hellish day.

First we get the Federal Reserve's interest rate decision at mid-afternoon where the policy statement could have far more impact than the policy action itself.

Then this evening we will at long last get some more information on the President's Social Security reform plan, where it is hoped he will move beyond the policy skeleton he has given us and put some meaty details on the proposal's bones.

In the Fed's case a slight shift in words, or in tone, could move the markets. If the Fed drops the word "measured" to describe the pace of rate hikes, if it shifts its policy bias to worry more about inflation, if it talks about inflation expectations heating up, that would be taken as a signal of more aggressive rate hikes ahead.

Let's remember though Greenspan's favorite inflation indicator, the "core PCE deflator" is running well under 2% annually. That doesn't seem to argue for any big Fed shift.

As for the President, he has laid out three broad principles for Social Security reform: don't touch current retirees' benefits, no payroll tax hike, and give workers the option to put some of their money in personal investment accounts.

If he really wants to get Social Security reformed, it's hard to see how he can continue to say no payroll tax hike. Because the numbers are such that one of three things, or a combination of them, HAS to be done: raise the payroll tax (boost the cap on taxable income which now stands at $90,000), trim benefits, or raise the retirement age. It's a question of numbers, not politics: more retirees collecting benefits, fewer younger workers entering the work force, and that means Social Security costs are rising. Period.

If the President can't tell the American people the cold, hard truth, who can? And depending on who you talk to the chances of personal accounts making up the difference are slim to none. So, details, details, details. With a few small words both the Fed and the White House could have a big impact.

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-- Kathleen Hays is economics correspondent for CNN and contributes to Lou Dobbs Tonight.