Majority Leader Harry Reid expressed confidence Friday that Senate Democrats will continue to increase their majority in 2010, but made it clear he doesn’t expect to add Pennsylvania’s Arlen Specter to his caucus.

“We’re in a position to pick up a number of seats,” Reid told reporters, adding that he believes Barack Obama ’s presidency will help them — even though a president’s party often loses seats in a mid-term election.

“We have a situation where we have a dynamic young president who has indicated he wants to change things in our country that need changing,” said Reid, D-Nev.

Reid declined to speculate about precisely how many seats the Democrats might gain next year.

“I’m not going to do that,” Reid said, adding that he “would like to have 60” — the number of votes needed to overcome a filibuster.

Reid acknowledged that he had reached out to Specter, a moderate Republican, to try to convince him to abandon the GOP. Democrats have long courted Specter, who is expected to draw a primary challenge in 2010.

But Reid said Specter effectively answered the question on March 24 by announcing he would vote against limiting debate on a major Democratic priority — so-called “card check” legislation that would ease union organizing rules.

“Yes, I’ve talked to him,” Reid said about Specter. “But I think he — in coming out against card check — kind of stopped everyone from being able to help him.”

In November, the Democrats expanded their majority to 58 seats, including two independents who caucus with the party — a gain of seven. With an unsettled race in Minnesota appearing to be trending the Democrats’ way, they could push their majority to 59 seats.

If Reid’s 2010 prediction turns out to be correct, Democrats will have dodged a bullet. A president’s party can be vulnerable in mid-term election years — such as 1994, when Republicans capitalized on public dissatisfaction with President Bill Clinton to sweep both chambers of Congress.

Strictly by the numbers, the Republicans face a better situation in 2010.

In 2008, the GOP had to defend 23 of its own seats, while Democrats had to defend 12. The ratio is not as lopsided in 2010: The GOP has 19 seats up for re-election, while the Democrats have 17 — and four of those are now held by appointees who filled vacancies created by senators who left to join the Obama administration.

Reid himself will be a Republican target. Although the GOP has yet to identify a challenger — former Rep. Jon Porter appears to be the most viable potential candidate — Reid has begun building a formidable war chest. He had $3.3 million in cash on hand as of Dec. 31, according to a report filed with the Federal Election Commission.